Update definition name in MockPostCodeLib.h

Author: TsunFeng

MdePkg/Test/Mock/Include/GoogleTest/Library/MockPostCodeLib.h

@@ -6,8 +6,8 @@
   SPDX-License-Identifier: BSD-2-Clause-Patent
 **/
 
-#ifndef MOCK_PCI_EXPRESS_LIB_H_
-#define MOCK_PCI_EXPRESS_LIB_H_
+#ifndef MOCK_POST_CODE_LIB_H_
+#define MOCK_POST_CODE_LIB_H_
 
 #include <Library/GoogleTestLib.h>
 #include <Library/FunctionMockLib.h>