gpu/drm/radeon: Fix spelling typo in comments

Fix spelling typo in comments.
Signed-off-by: pengfuyuan <pengfuyuan@kylinos.cn>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/radeon/atombios.h

@@ -3599,7 +3599,7 @@ typedef struct  _ATOM_LCD_RTS_RECORD
   UCHAR     ucRTSValue;
 }ATOM_LCD_RTS_RECORD;
 
-//!! If the record below exits, it should always be the first record for easy use in command table!!!
+//!! If the record below exists, it should always be the first record for easy use in command table!!!
 // The record below is only used when LVDS_Info is present. From ATOM_LVDS_INFO_V12, use ucLCDPanel_SpecialHandlingCap instead.
 typedef struct  _ATOM_LCD_MODE_CONTROL_CAP
 {
@@ -5973,7 +5973,7 @@ typedef struct _ATOM_ASIC_INTERNAL_SS_INFO_V3
 #define CLEAR_ATOM_S7_DOS_8BIT_DAC_EN         ((ATOM_DOS_MODE_INFO_DEF << 8 )|ATOM_S7_DOS_8BIT_DAC_EN_SHIFT | ATOM_FLAG_CLEAR )
 
 /****************************************************************************/	
-//Portion II: Definitinos only used in Driver
+//Portion II: Definitions only used in Driver
 /****************************************************************************/
 
 // Macros used by driver
@@ -7162,7 +7162,7 @@ typedef struct _DP_ENCODER_SERVICE_PARAMETERS
 
 // ucAction
 #define ATOM_DP_ACTION_GET_SINK_TYPE							0x01
-/* obselete */
+/* obsolete */
 #define ATOM_DP_ACTION_TRAINING_START							0x02
 #define ATOM_DP_ACTION_TRAINING_COMPLETE					0x03
 #define ATOM_DP_ACTION_TRAINING_PATTERN_SEL				0x04