drm/radeon: silence UBSAN warning (v3)

Convert a variable sized array from [1] to [].

v2: fix up a few more.
v3: integrate comments from Kees.
Reviewed-by: Kees Cook <keescook@chromium.org>
Tested-by: Jeff Johnson <quic_jjohnson@quicinc.com> (v2)
Acked-by: Christian König <christian.koenig@amd.com> (v1)
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: keescook@chromium.org

drivers/gpu/drm/radeon/pptable.h

@@ -424,7 +424,7 @@ typedef struct _ATOM_PPLIB_SUMO_CLOCK_INFO{
 typedef struct _ATOM_PPLIB_STATE_V2
 {
       //number of valid dpm levels in this state; Driver uses it to calculate the whole 
-      //size of the state: sizeof(ATOM_PPLIB_STATE_V2) + (ucNumDPMLevels - 1) * sizeof(UCHAR)
+      //size of the state: struct_size(ATOM_PPLIB_STATE_V2, clockInfoIndex, ucNumDPMLevels)
       UCHAR ucNumDPMLevels;
       
       //a index to the array of nonClockInfos
@@ -432,14 +432,14 @@ typedef struct _ATOM_PPLIB_STATE_V2
       /**
       * Driver will read the first ucNumDPMLevels in this array
       */
-      UCHAR clockInfoIndex[1];
+      UCHAR clockInfoIndex[] __counted_by(ucNumDPMLevels);
 } ATOM_PPLIB_STATE_V2;
 
 typedef struct _StateArray{
     //how many states we have 
     UCHAR ucNumEntries;
     
-    ATOM_PPLIB_STATE_V2 states[1];
+    ATOM_PPLIB_STATE_V2 states[] __counted_by(ucNumEntries);
 }StateArray;
 
 
@@ -450,7 +450,7 @@ typedef struct _ClockInfoArray{
     //sizeof(ATOM_PPLIB_CLOCK_INFO)
     UCHAR ucEntrySize;
     
-    UCHAR clockInfo[1];
+    UCHAR clockInfo[] __counted_by(ucNumEntries);
 }ClockInfoArray;
 
 typedef struct _NonClockInfoArray{
@@ -460,7 +460,7 @@ typedef struct _NonClockInfoArray{
     //sizeof(ATOM_PPLIB_NONCLOCK_INFO)
     UCHAR ucEntrySize;
     
-    ATOM_PPLIB_NONCLOCK_INFO nonClockInfo[1];
+    ATOM_PPLIB_NONCLOCK_INFO nonClockInfo[] __counted_by(ucNumEntries);
 }NonClockInfoArray;
 
 typedef struct _ATOM_PPLIB_Clock_Voltage_Dependency_Record