MdeModulePkg: Use EfiEventEmptyFunction from UefiLib

Use EfiEventEmptyFunction from UefiLib and remove the duplication
of event empty function.

REF: https://bugzilla.tianocore.org/show_bug.cgi?id=298

Cc: Feng Tian <feng.tian@intel.com>
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Cc: Liming Gao <liming.gao@intel.com>
Cc: Michael Kinney <michael.d.kinney@intel.com>
Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Star Zeng <star.zeng@intel.com>
Reviewed-by: Feng Tian <feng.tian@intel.com>

MdeModulePkg/Universal/Console/ConSplitterDxe/ConSplitter.c

@@ -16,7 +16,7 @@
   never removed. Such design ensures sytem function well during none console
   device situation.
 
-Copyright (c) 2006 - 2016, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2006 - 2017, Intel Corporation. All rights reserved.<BR>
 (C) Copyright 2016 Hewlett Packard Enterprise Development LP<BR>
 This program and the accompanying materials
 are licensed and made available under the terms and conditions of the BSD License
@@ -711,7 +711,7 @@ ConSplitterTextInConstructor (
   Status = gBS->CreateEventEx (
                   EVT_NOTIFY_SIGNAL,
                   TPL_CALLBACK,
-                  ConSplitterEmptyCallbackFunction,
+                  EfiEventEmptyFunction,
                   NULL,
                   &gConnectConInEventGuid,
                   &ConInPrivate->ConnectConInEvent
@@ -4979,21 +4979,3 @@ ConSplitterTextOutEnableCursor (
 
   return ReturnStatus;
 }
-
-
-/**
-  An empty function to pass error checking of CreateEventEx ().
-
-  @param  Event                 Event whose notification function is being invoked.
-  @param  Context               Pointer to the notification function's context,
-                                which is implementation-dependent.
-
-**/
-VOID
-EFIAPI
-ConSplitterEmptyCallbackFunction (
-  IN EFI_EVENT                Event,
-  IN VOID                     *Context
-  )
-{
-}