DynamicTablesPkg: 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: Sami Mujawar <sami.mujawar@arm.com>

DynamicTablesPkg/Library/Common/AmlLib/Tree/AmlTreeEnumerator.c

@@ -35,7 +35,7 @@ EFIAPI
 AmlEnumTree (
   IN      AML_NODE_HEADER               * Node,
   IN      EDKII_AML_TREE_ENUM_CALLBACK    CallBack,
-  IN  OUT VOID                          * Context,  OPTIONAL
+  IN  OUT VOID                          * Context   OPTIONAL,
       OUT EFI_STATUS                    * Status    OPTIONAL
   )
 {