md/bitmap: remove redundant return in bitmap_checkpage

The "return 0" is not needed since bitmap_checkpage
will finally return 0 for the case.
Signed-off-by: Guoqing Jiang <gqjiang@suse.com>
Signed-off-by: Shaohua Li <shli@fb.com>

drivers/md/bitmap.c

@@ -98,7 +98,6 @@ __acquires(bitmap->lock)
 		   bitmap->bp[page].hijacked) {
 		/* somebody beat us to getting the page */
 		kfree(mappage);
-		return 0;
 	} else {
 
 		/* no page was in place and we have one, so install it */