MdePkg: Add Ipmi2.0 definitions head file.

Re-add Ipmi2.0 definitions header files based on Ipmi category:
App, Storage and etc.
In V3, the file name has been changed for short.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Daocheng Bu <daocheng.bu@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@19272 6f19259b-4bc3-4df7-8a09-765794883524

MdePkg/Include/IndustryStandard/IpmiNetFnGroupExtension.h

@@ -0,0 +1,26 @@
+/** @file
+  IPMI 2.0 definitions from the IPMI Specification Version 2.0, Revision 1.1.
+
+  Copyright (c) 1999 - 2015, 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 _IPMI_NET_FN_GROUP_EXTENSION_H_
+#define _IPMI_NET_FN_GROUP_EXTENSION_H_
+
+//
+// Net function definition for Group Extension command
+//
+#define IPMI_NETFN_GROUP_EXT  0x2C
+
+//
+// All Group Extension commands and their structure definitions to follow here
+//
+
+#endif