[TCBZ3351] ArmPlatformPkg: Update LcdHwNullLib to prevent init

Library previously returned EFI_SUCCESS which causes the platform to
continue initializing LCD HW. Should return EFI_NOT_FOUND.

ArmPlatformPkg/Library/LcdHwNullLib/LcdHwNullLib.c

@@ -23,7 +23,7 @@ LcdIdentify (
   VOID
   )
 {
-  return EFI_SUCCESS;
+  return EFI_NOT_FOUND;   // MU_CHANGE TCBZ3351 - Prevent further LCD init.
 }
 
 /**