NetworkPkg: Change complex DEBUG_CODE() to DEBUG_CODE_BEGIN/END()

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=3767

Update use of DEBUG_CODE(Expression) if Expression is a complex code
block with if/while/for/case statements that use {}.

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: Maciej Rabeda <maciej.rabeda@linux.intel.com>

NetworkPkg/MnpDxe/MnpConfig.c

@@ -1669,7 +1669,7 @@ MnpConfigReceiveFilters (
                   MCastFilterCnt,
                   MCastFilter
                   );
-  DEBUG_CODE (
+  DEBUG_CODE_BEGIN ();
     if (EFI_ERROR (Status)) {
       DEBUG (
         (DEBUG_ERROR,
@@ -1677,7 +1677,7 @@ MnpConfigReceiveFilters (
         Status)
         );
     }
-  );
+  DEBUG_CODE_END ();
 
   if (MCastFilter != NULL) {
     //

NetworkPkg/MnpDxe/MnpIo.c

@@ -898,11 +898,11 @@ MnpReceivePacket (
   //
   Status = Snp->Receive (Snp, &HeaderSize, &BufLen, BufPtr, NULL, NULL, NULL);
   if (EFI_ERROR (Status)) {
-    DEBUG_CODE (
+    DEBUG_CODE_BEGIN ();
       if (Status != EFI_NOT_READY) {
         DEBUG ((DEBUG_WARN, "MnpReceivePacket: Snp->Receive() = %r.\n", Status));
       }
-    );
+    DEBUG_CODE_END ();
 
     return Status;
   }