drm/amdgpu: Replace one-element array with flex-array member

One-element arrays are deprecated, and we are replacing them with
flexible array members instead. So, replace one-element array with
flexible-array member in structs _ATOM_CONNECTOR_DEVICE_TAG_RECORD,
_ATOM_OBJECT_GPIO_CNTL_RECORD, _ATOM_BRACKET_LAYOUT_RECORD,
_ATOM_BRACKET_LAYOUT_RECORD, _ATOM_LEAKAGE_VOLTAGE_OBJECT_V3,
_ATOM_FUSION_SYSTEM_INFO_V3, _ATOM_I2C_DATA_RECORD,
_ATOM_I2C_DEVICE_SETUP_INFO, _ATOM_ASIC_MVDD_INFO and refactor the
rest of the code accordingly. While at it, removed a redundant casting.

Important to mention is that doing a build before/after this patch results
in no binary output differences.

This helps with the ongoing efforts to tighten the FORTIFY_SOURCE
routines on memcpy() and help us make progress towards globally
enabling -fstrict-flex-arrays=3 [1].

Link: https://github.com/KSPP/linux/issues/79
Link: https://github.com/KSPP/linux/issues/238
Link: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101836 [1]
Signed-off-by: Paulo Miguel Almeida <paulo.miguel.almeida.rodenas@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/display/dc/bios/bios_parser.c

@@ -2606,8 +2606,7 @@ static enum bp_result update_slot_layout_info(
 
 	for (;;) {
 
-		record_header = (ATOM_COMMON_RECORD_HEADER *)
-			GET_IMAGE(ATOM_COMMON_RECORD_HEADER, record_offset);
+		record_header = GET_IMAGE(ATOM_COMMON_RECORD_HEADER, record_offset);
 		if (record_header == NULL) {
 			result = BP_RESULT_BADBIOSTABLE;
 			break;
@@ -2621,7 +2620,7 @@ static enum bp_result update_slot_layout_info(
 
 		if (record_header->ucRecordType ==
 			ATOM_BRACKET_LAYOUT_RECORD_TYPE &&
-			sizeof(ATOM_BRACKET_LAYOUT_RECORD)
+			struct_size(record, asConnInfo, 1)
 			<= record_header->ucRecordSize) {
 			record = (ATOM_BRACKET_LAYOUT_RECORD *)
 				(record_header);

drivers/gpu/drm/amd/include/atombios.h

@@ -4733,7 +4733,7 @@ typedef struct  _ATOM_CONNECTOR_DEVICE_TAG_RECORD
   ATOM_COMMON_RECORD_HEADER   sheader;
   UCHAR                       ucNumberOfDevice;
   UCHAR                       ucReserved;
-  ATOM_CONNECTOR_DEVICE_TAG   asDeviceTag[1];         //This Id is same as "ATOM_DEVICE_XXX_SUPPORT", 1 is only for allocation
+  ATOM_CONNECTOR_DEVICE_TAG   asDeviceTag[];	       //This Id is same as "ATOM_DEVICE_XXX_SUPPORT"
 }ATOM_CONNECTOR_DEVICE_TAG_RECORD;
 
 
@@ -4793,7 +4793,7 @@ typedef struct  _ATOM_OBJECT_GPIO_CNTL_RECORD
   ATOM_COMMON_RECORD_HEADER   sheader;
   UCHAR                       ucFlags;                // Future expnadibility
   UCHAR                       ucNumberOfPins;         // Number of GPIO pins used to control the object
-  ATOM_GPIO_PIN_CONTROL_PAIR  asGpio[1];              // the real gpio pin pair determined by number of pins ucNumberOfPins
+  ATOM_GPIO_PIN_CONTROL_PAIR  asGpio[];               // the real gpio pin pair determined by number of pins ucNumberOfPins
 }ATOM_OBJECT_GPIO_CNTL_RECORD;
 
 //Definitions for GPIO pin state
@@ -4982,7 +4982,7 @@ typedef struct  _ATOM_BRACKET_LAYOUT_RECORD
   UCHAR                       ucWidth;
   UCHAR                       ucConnNum;
   UCHAR                       ucReserved;
-  ATOM_CONNECTOR_LAYOUT_INFO  asConnInfo[1];
+  ATOM_CONNECTOR_LAYOUT_INFO  asConnInfo[];
 }ATOM_BRACKET_LAYOUT_RECORD;
 
 
@@ -5161,7 +5161,7 @@ typedef struct  _ATOM_GPIO_VOLTAGE_OBJECT_V3
    UCHAR  ucPhaseDelay;                      // phase delay in unit of micro second
    UCHAR  ucReserved;
    ULONG  ulGpioMaskVal;                     // GPIO Mask value
-   VOLTAGE_LUT_ENTRY_V2 asVolGpioLut[1];
+   VOLTAGE_LUT_ENTRY_V2 asVolGpioLut[];
 }ATOM_GPIO_VOLTAGE_OBJECT_V3;
 
 typedef struct  _ATOM_LEAKAGE_VOLTAGE_OBJECT_V3
@@ -5171,7 +5171,7 @@ typedef struct  _ATOM_LEAKAGE_VOLTAGE_OBJECT_V3
    UCHAR    ucLeakageEntryNum;               // indicate the entry number of LeakageId/Voltage Lut table
    UCHAR    ucReserved[2];
    ULONG    ulMaxVoltageLevel;
-   LEAKAGE_VOLTAGE_LUT_ENTRY_V2 asLeakageIdLut[1];
+   LEAKAGE_VOLTAGE_LUT_ENTRY_V2 asLeakageIdLut[];
 }ATOM_LEAKAGE_VOLTAGE_OBJECT_V3;
 
 
@@ -6599,7 +6599,7 @@ typedef struct _ATOM_FUSION_SYSTEM_INFO_V3
 typedef struct _ATOM_I2C_DATA_RECORD
 {
   UCHAR         ucNunberOfBytes;                                              //Indicates how many bytes SW needs to write to the external ASIC for one block, besides to "Start" and "Stop"
-  UCHAR         ucI2CData[1];                                                 //I2C data in bytes, should be less than 16 bytes usually
+  UCHAR         ucI2CData[];                                                  //I2C data in bytes, should be less than 16 bytes usually
 }ATOM_I2C_DATA_RECORD;
 
 
@@ -6610,14 +6610,14 @@ typedef struct _ATOM_I2C_DEVICE_SETUP_INFO
   UCHAR                              ucSSChipID;             //SS chip being used
   UCHAR                              ucSSChipSlaveAddr;      //Slave Address to set up this SS chip
   UCHAR                           ucNumOfI2CDataRecords;  //number of data block
-  ATOM_I2C_DATA_RECORD            asI2CData[1];
+  ATOM_I2C_DATA_RECORD            asI2CData[];
 }ATOM_I2C_DEVICE_SETUP_INFO;
 
 //==========================================================================================
 typedef struct  _ATOM_ASIC_MVDD_INFO
 {
   ATOM_COMMON_TABLE_HEADER         sHeader;
-  ATOM_I2C_DEVICE_SETUP_INFO      asI2CSetup[1];
+  ATOM_I2C_DEVICE_SETUP_INFO      asI2CSetup[];
 }ATOM_ASIC_MVDD_INFO;
 
 //==========================================================================================