Refine code to make it more safely.

Contributed-under: TianoCore Contribution Agreement 1.0
Signed-off-by: Eric Dong <eric.dong@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>

git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@15595 6f19259b-4bc3-4df7-8a09-765794883524

EdkCompatibilityPkg/Foundation/Library/Dxe/EfiUiLib/EfiUiLib.c

@@ -1,6 +1,6 @@
 /*++
 
-Copyright (c) 2007 - 2010, Intel Corporation. All rights reserved.<BR>
+Copyright (c) 2007 - 2014, 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        
@@ -214,6 +214,8 @@ Arguments:
   UINTN         Rem;
   static CHAR16 *SizeUnits[] = { L" B", L" kB", L" MB", L" GB", L" TB", L" PB" };
 
+  Rem = 0;
+
   for (i = 0; i < (sizeof (SizeUnits) / sizeof (SizeUnits)[0]); i++) {
 
     DivU64x32 (Val, 1024, &Rem);