drm/radeon: Replace 1-element arrays with flexible-array members

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_DISPLAY_OBJECT_PATH,
_ATOM_DISPLAY_OBJECT_PATH_TABLE, _ATOM_OBJECT_TABLE, GOP_VBIOS_CONTENT
_ATOM_GPIO_VOLTAGE_OBJECT_V3 and refactor the rest of the code accordingly.

It's worth mentioning 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/239
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/radeon/atombios.h

@@ -4020,7 +4020,7 @@ typedef struct  _ATOM_DISPLAY_OBJECT_PATH
   USHORT    usSize;                                        //the size of ATOM_DISPLAY_OBJECT_PATH
   USHORT    usConnObjectId;                                //Connector Object ID 
   USHORT    usGPUObjectId;                                 //GPU ID 
-  USHORT    usGraphicObjIds[1];                             //1st Encoder Obj source from GPU to last Graphic Obj destinate to connector.
+  USHORT    usGraphicObjIds[];                             //1st Encoder Obj source from GPU to last Graphic Obj destinate to connector.
 }ATOM_DISPLAY_OBJECT_PATH;
 
 typedef struct  _ATOM_DISPLAY_EXTERNAL_OBJECT_PATH
@@ -4037,7 +4037,7 @@ typedef struct _ATOM_DISPLAY_OBJECT_PATH_TABLE
   UCHAR                           ucNumOfDispPath;
   UCHAR                           ucVersion;
   UCHAR                           ucPadding[2];
-  ATOM_DISPLAY_OBJECT_PATH        asDispPath[1];
+  ATOM_DISPLAY_OBJECT_PATH        asDispPath[];
 }ATOM_DISPLAY_OBJECT_PATH_TABLE;
 
 
@@ -4053,7 +4053,7 @@ typedef struct _ATOM_OBJECT_TABLE                         //Above 4 object table
 {
   UCHAR               ucNumberOfObjects;
   UCHAR               ucPadding[3];
-  ATOM_OBJECT         asObjects[1];
+  ATOM_OBJECT         asObjects[];
 }ATOM_OBJECT_TABLE;
 
 typedef struct _ATOM_SRC_DST_TABLE_FOR_ONE_OBJECT         //usSrcDstTableOffset pointing to this structure
@@ -4615,7 +4615,7 @@ 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
@@ -7964,7 +7964,7 @@ typedef struct {
 
 typedef struct {
   VFCT_IMAGE_HEADER	VbiosHeader;
-  UCHAR	VbiosContent[1];
+  UCHAR	VbiosContent[];
 }GOP_VBIOS_CONTENT;
 
 typedef struct {