MdePkg: Add new definitions for Management Mode.

In PI 1.5 version, system management mode name(SMM) has been changed
to Management Mode(MM). It impacts the current code which still use
SMM/Smram/SMI keywords. This patch add new definition which use
MM/MmRam/MMI keywords to follow new spec definitions.

Cc: Michael D Kinney <michael.d.kinney@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Eric Dong <eric.dong@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>

MdePkg/Include/Protocol/MmReadyToLock.h

@@ -0,0 +1,32 @@
+/** @file
+  MM Ready To Lock protocol introduced in the PI 1.5 specification.
+
+  This protocol is a mandatory protocol published by the MM Foundation
+  code when the system is preparing to lock certain resources and interfaces
+  in anticipation of the invocation of 3rd party extensible modules.
+  This protocol is an MM counterpart of the DXE MM Ready to Lock Protocol.
+  This protocol prorogates resource locking notification into MM environment.
+  This protocol is installed after installation of the MM End of DXE Protocol.
+
+  Copyright (c) 2017, Intel Corporation. All rights reserved.<BR>
+  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
+  http://opensource.org/licenses/bsd-license.php
+
+  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
+  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
+
+**/
+
+#ifndef _MM_READY_TO_LOCK_H_
+#define _MM_READY_TO_LOCK_H_
+
+#define EFI_MM_READY_TO_LOCK_PROTOCOL_GUID \
+  { \
+    0x47b7fa8c, 0xf4bd, 0x4af6, { 0x82, 0x00, 0x33, 0x30, 0x86, 0xf0, 0xd2, 0xc8 } \
+  }
+
+extern EFI_GUID gEfiMmReadyToLockProtocolGuid;
+
+#endif