dm bufio: Remove NULL check of list_entry()

list_entry() will never return a NULL pointer, thus remove the
check.
Signed-off-by: Yuesong Li <liyuesong@vivo.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>

drivers/md/dm-bufio.c

@@ -529,9 +529,6 @@ static struct dm_buffer *list_to_buffer(struct list_head *l)
 {
 	struct lru_entry *le = list_entry(l, struct lru_entry, list);
 
-	if (!le)
-		return NULL;
-
 	return le_to_buffer(le);
 }