Change Fat driver to support asynchronous File IO introduced in UEFI spec 2.3.1.D.

Signed-off-by: Ruiyu Ni <ruiyu.ni@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>

(based on FatPkg commit 063f6e8a9c263bafd52e1226399fc64d6d721dca)

[jordan.l.justen@intel.com: Use script to relicense to 2-clause BSD]
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Acked-by: Mark Doran <mark.doran@intel.com>
Acked-by: Laszlo Ersek <lersek@redhat.com>

FatPkg/EnhancedFatDxe/Data.c

@@ -1,6 +1,6 @@
 /*++
 
-Copyright (c) 2005 - 2009, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2005 - 2013, 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
@@ -30,7 +30,9 @@ Revision History
 //
 // FatFsLock - Global lock for synchronizing all requests.
 //
-EFI_LOCK FatFsLock = EFI_INITIALIZE_LOCK_VARIABLE(TPL_CALLBACK);
+EFI_LOCK FatFsLock   = EFI_INITIALIZE_LOCK_VARIABLE (TPL_CALLBACK);
+
+EFI_LOCK FatTaskLock = EFI_INITIALIZE_LOCK_VARIABLE (TPL_NOTIFY);
 
 //
 // Filesystem interface functions
@@ -46,5 +48,9 @@ EFI_FILE_PROTOCOL               FatFileInterface = {
   FatSetPosition,
   FatGetInfo,
   FatSetInfo,
-  FatFlush
+  FatFlush,
+  FatOpenEx,
+  FatReadEx,
+  FatWriteEx,
+  FatFlushEx
 };