uml: const and other tidying

This patch also does some improvements for uml code.  Improvements include
dropping unnecessary cast, killing some unnecessary code and still some
constifying for pointers etc..

Signed-off-by: WANG Cong <xiyou.wangcong@gmail.com>
Signed-off-by: Jeff Dike <jdike@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c
index e3e7241..96072e2 100644
--- a/arch/um/kernel/mem.c
+++ b/arch/um/kernel/mem.c
@@ -65,7 +65,7 @@
 void __init mem_init(void)
 {
 	/* clear the zero-page */
-	memset((void *) empty_zero_page, 0, PAGE_SIZE);
+	memset(empty_zero_page, 0, PAGE_SIZE);
 
 	/* Map in the area just after the brk now that kmalloc is about
 	 * to be turned on.