Fix 3 bugs in DiskIoDxe and PartitionDxe drivers introduced in DiskIo2 implementation.

1. DiskIo2 shouldn't signal the event when the *Ex interface returns failure status per the UEFI spec.
2. PartitionDxe should close DiskIo2 protocol when error happens in DriverBindingStart() otherwise Fat driver cannot open the DiskIo2 BY_DRIVER.
3. PartitionDxe should create event using TPL_NOTIFY instead of TPL_CALLBACK otherwise asynchronous FileIo may be blocked.

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

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@14680 6f19259b-4bc3-4df7-8a09-765794883524

MdeModulePkg/Universal/Disk/PartitionDxe/Partition.c

@@ -352,11 +352,11 @@ PartitionDriverBindingStart (
           ControllerHandle
           );
     //
-    // Close Parent BlockIO2 if has.
+    // Close Parent DiskIo2 if has.
     //    
     gBS->CloseProtocol (
            ControllerHandle,
-           &gEfiBlockIo2ProtocolGuid,
+           &gEfiDiskIo2ProtocolGuid,
            This->DriverBindingHandle,
            ControllerHandle
            );
@@ -822,7 +822,7 @@ PartitionCreateAccessTask (
 
   Status = gBS->CreateEvent (
                   EVT_NOTIFY_SIGNAL,
-                  TPL_CALLBACK,
+                  TPL_NOTIFY,
                   PartitionOnAccessComplete,
                   Task,
                   &Task->DiskIo2Token.Event