Clarify the UEFI/EFI specification version in file header comments.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@9238 6f19259b-4bc3-4df7-8a09-765794883524

MdePkg/Include/Protocol/PxeBaseCodeCallBack.h

@@ -1,9 +1,8 @@
 /** @file
-  EFI PXE Base Code CallBack Protocol is as defined in UEFI specification.
   It is invoked when the PXE Base Code Protocol is about to transmit, has received, 
   or is waiting to receive a packet.
 
-  Copyright (c) 2006 - 2008, Intel Corporation                                                         
+  Copyright (c) 2006 - 2009, Intel Corporation                                                         
   All rights reserved. This program and the accompanying materials                          
   are licensed and made available under the terms and conditions of the BSD License         
   which accompanies this distribution.  The full text of the license may be found at        
@@ -12,6 +11,9 @@
   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,                     
   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.             
 
+  @par Revision Reference:          
+  This Protocol is introduced in EFI Specification 1.10
+
 **/
 
 #ifndef _PXE_BASE_CODE_CALLBACK_H_