[PATCH] lib/string.c cleanup: restore useful memmove const

A couple of (char *) casts removed in a previous cleanup patch in
lib/string.c:memmove() were actually useful, as they suppressed a couple of
warnings:

	assignment discards qualifiers from pointer target type

Fix by declaring the local variable const in the first place, so casts
aren't needed to strip the const qualifier.
Signed-off-by: NPaul Jackson <pj@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

lib/string.c

@@ -488,7 +488,8 @@ EXPORT_SYMBOL(memcpy);
  */
 void *memmove(void *dest, const void *src, size_t count)
 {
-	char *tmp, *s;
+	char *tmp;
+	const char *s;
 
 	if (dest <= src) {
 		tmp = dest;