Move lock to FAT driver binding start to prevent interrupt during hot plug event.

(based on FatPkg commit b449ca31443f754ed2e6998ca32f49547dabd615)

[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/Init.c

@@ -51,8 +51,7 @@ Returns:
 {
   EFI_STATUS  Status;
   FAT_VOLUME  *Volume;
-  BOOLEAN     LockedByMe;
-  LockedByMe = FALSE;
+
   //
   // Allocate a volume structure
   //
@@ -60,14 +59,7 @@ Returns:
   if (Volume == NULL) {
     return EFI_OUT_OF_RESOURCES;
   }
-  //
-  // Acquire the lock.
-  // If caller has already acquired the lock, cannot lock it again.
-  //
-  Status = FatAcquireLockOrFail ();
-  if (!EFI_ERROR (Status)) {
-    LockedByMe = TRUE;
-  }
+
   //
   // Initialize the structure
   //
@@ -119,13 +111,6 @@ Returns:
   Volume->Valid = TRUE;
 
 Done:
-  //
-  // Unlock if locked by myself.
-  //
-  if (LockedByMe) {
-    FatReleaseLock ();
-  }
-
   if (EFI_ERROR (Status)) {
     FatFreeVolume (Volume);
   }