FatPkg/EnhancedFatDxe: Make function prototype align with definition

Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Dandan Bi <dandan.bi@intel.com>
Reviewed-by: Ruiyu Ni <ruiyu.ni@intel.com>

FatPkg/EnhancedFatDxe/Info.c

@@ -34,8 +34,8 @@ FatGetVolumeInfo (
 EFI_STATUS
 FatSetVolumeInfo (
   IN FAT_VOLUME       *Volume,
-  IN OUT UINTN        BufferSize,
+  IN UINTN            BufferSize,
-  OUT VOID            *Buffer
+  IN VOID            *Buffer
   );
 
 EFI_STATUS