block: simplify the check for the current elevator in elv_iosched_show

Just compare the pointers instead of using the string based
elevator_match.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20221030100714.876891-6-hch@lst.de
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/elevator.c

@@ -792,7 +792,7 @@ ssize_t elv_iosched_show(struct request_queue *q, char *name)
 
 	spin_lock(&elv_list_lock);
 	list_for_each_entry(e, &elv_list, list) {
-		if (cur && elevator_match(cur, e->elevator_name, 0)) {
+		if (e == cur) {
 			len += sprintf(name+len, "[%s] ", cur->elevator_name);
 			continue;
 		}