UefiPayloadPkg: 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: Ray Ni <ray.ni@intel.com>

UefiPayloadPkg/Include/Library/SpiFlashLib.h

@@ -207,9 +207,8 @@ EFI_STATUS
 EFIAPI
 SpiGetRegionAddress (
   IN     FLASH_REGION_TYPE  FlashRegionType,
-  OUT    UINT32             *BaseAddress, OPTIONAL
+  OUT    UINT32             *BaseAddress  OPTIONAL,
   OUT    UINT32             *RegionSize OPTIONAL
   );
 
 #endif
-