MdePkg/Library/BaseLib: Enable VS2017/ARM64 builds

Required GCC assembly files are converted for the MSFT assembler

Contributed-under: TianoCore Contribution Agreement 1.1
Signed-off-by: Pete Batard <pete@akeo.ie>
Reviewed-by: Liming Gao <liming.gao@intel.com>

MdePkg/Library/BaseLib/AArch64/MemoryFence.asm

@@ -0,0 +1,38 @@
+;------------------------------------------------------------------------------
+;
+; MemoryFence() for AArch64
+;
+; Copyright (c) 2013, ARM Ltd. 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
+; 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.
+;
+;------------------------------------------------------------------------------
+
+  EXPORT MemoryFence
+  AREA BaseLib_LowLevel, CODE, READONLY
+
+;/**
+;  Used to serialize load and store operations.
+;
+;  All loads and stores that proceed calls to this function are guaranteed to be
+;  globally visible when this function returns.
+;
+;**/
+;VOID
+;EFIAPI
+;MemoryFence (
+;  VOID
+;  );
+;
+MemoryFence
+    // System wide Data Memory Barrier.
+    dmb sy
+    ret
+
+  END