OvmfPkg/VirtioGpuDxe: Check QueryMode arguments

The current implementation does not check if Info or SizeInfo
pointers are NULL. This causes the SCT test suite to crash.

Add a check to return EFI_INVALID_PARAMETER if any of these
pointers are NULL.

Signed-off-by: Dimitrije Pavlov <Dimitrije.Pavlov@arm.com>
Reviewed-by: Sunny Wang <sunny.wang@arm.com>

OvmfPkg/VirtioGpuDxe/Gop.c

@@ -308,7 +308,10 @@ GopQueryMode (
 {
   EFI_GRAPHICS_OUTPUT_MODE_INFORMATION  *GopModeInfo;
 
-  if (ModeNumber >= This->Mode->MaxMode) {
+  if ((Info == NULL) ||
+      (SizeOfInfo == NULL) ||
+      (ModeNumber >= This->Mode->MaxMode))
+  {
     return EFI_INVALID_PARAMETER;
   }