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/Serialize/AmlSerialize.c

@@ -39,7 +39,7 @@ BOOLEAN
 EFIAPI
 AmlSerializeNodeCallback (
   IN       AML_NODE_HEADER   * Node,
-  IN  OUT  VOID              * Context,    OPTIONAL
+  IN  OUT  VOID              * Context     OPTIONAL,
   IN  OUT  EFI_STATUS        * Status      OPTIONAL
   )
 {
@@ -170,7 +170,7 @@ EFI_STATUS
 EFIAPI
 AmlSerializeTree (
   IN      AML_ROOT_NODE   * RootNode,
-  IN      UINT8           * Buffer,     OPTIONAL
+  IN      UINT8           * Buffer      OPTIONAL,
   IN  OUT UINT32          * BufferSize
   )
 {