EmulatorPkg: 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>

EmulatorPkg/Library/SecPeiServicesLib/PeiServicesLib.c

@@ -548,14 +548,13 @@ PeiServicesFfsGetVolumeInfo (
 VOID
 EFIAPI
 PeiServicesInstallFvInfoPpi (
-  IN CONST EFI_GUID                *FvFormat, OPTIONAL
+  IN CONST EFI_GUID                *FvFormat  OPTIONAL,
   IN CONST VOID                    *FvInfo,
   IN       UINT32                  FvInfoSize,
-  IN CONST EFI_GUID                *ParentFvName, OPTIONAL
+  IN CONST EFI_GUID                *ParentFvName  OPTIONAL,
   IN CONST EFI_GUID                *ParentFileName OPTIONAL
   )
 {
   ASSERT (FALSE);
   return;
 }
-