MdePkg: Change OPTIONAL keyword usage style

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3760

Update all use of ', OPTIONAL' to ' OPTIONAL,' for function params.

Cc: Andrew Fish <afish@apple.com>
Cc: Leif Lindholm <leif@nuviainc.com>
Cc: Michael Kubacki <michael.kubacki@microsoft.com>
Signed-off-by: Michael D Kinney <michael.d.kinney@intel.com>
Reviewed-by: Liming Gao <gaoliming@byosoft.com.cn>

MdePkg/Include/Protocol/UgaDraw.h

@@ -134,7 +134,7 @@ typedef
 EFI_STATUS
 (EFIAPI *EFI_UGA_DRAW_PROTOCOL_BLT)(
   IN  EFI_UGA_DRAW_PROTOCOL                   * This,
-  IN  EFI_UGA_PIXEL                           * BltBuffer, OPTIONAL
+  IN  EFI_UGA_PIXEL                           * BltBuffer  OPTIONAL,
   IN  EFI_UGA_BLT_OPERATION                   BltOperation,
   IN  UINTN                                   SourceX,
   IN  UINTN                                   SourceY,