Short term fix to pass some GCC warning.

(It should be able to remove R8Lib.c & R8Lib.h with APIs in BaseLib & PrintLib.)

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@4810 6f19259b-4bc3-4df7-8a09-765794883524

MdePkg/Library/IfrSupportLib/R8Lib.c

@@ -128,7 +128,7 @@ R8_BufToHexString (
 EFI_STATUS
 R8_HexStringToBuf (
   IN OUT UINT8                     *Buf,
-  IN OUT UINTN                    *Len,
+  IN OUT UINTN                     *Len,
   IN     CHAR16                    *Str,
   OUT    UINTN                     *ConvertedStrLen  OPTIONAL
   )
@@ -145,6 +145,7 @@ R8_HexStringToBuf (
   UINT8       Digit;
   UINT8       Byte;
 
+  Digit = 0;
   //
   // Find out how many hex characters the string has.
   //