MdePkg: introduce standalone MM entry point library implementation

Add an implementation of the StandaloneMmDriverEntryPoint library
class.

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Acked-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>

MdePkg/Library/StandaloneMmDriverEntryPoint/StandaloneMmDriverEntryPoint.inf

@@ -0,0 +1,43 @@
+## @file
+# Module entry point library for Standalone MM driver.
+#
+# Copyright (c) 2015, Intel Corporation. All rights reserved.<BR>
+# Copyright (c) 2016-2018, ARM Ltd. All rights reserved.<BR>
+# Copyright (c) 2018, Linaro, Limited. 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.
+#
+#
+##
+
+[Defines]
+  INF_VERSION                    = 0x0001001B
+  BASE_NAME                      = StandaloneMmDriverEntryPoint
+  MODULE_UNI_FILE                = StandaloneMmDriverEntryPoint.uni
+  FILE_GUID                      = 5ca126c0-b598-4f4b-abb9-b6e7d077aea9
+  MODULE_TYPE                    = MM_STANDALONE
+  VERSION_STRING                 = 1.0
+  PI_SPECIFICATION_VERSION       = 0x00010032
+  LIBRARY_CLASS                  = StandaloneMmDriverEntryPoint|MM_STANDALONE
+
+#
+# The following information is for reference only and not required by the build tools.
+#
+#  VALID_ARCHITECTURES           = IA32 X64 AARCH64
+#
+
+[Sources]
+  StandaloneMmDriverEntryPoint.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  BaseLib
+  DebugLib
+  MmServicesTableLib