block: use helper function to test queue register

We have defined common interface blk_queue_registered() to
test QUEUE_FLAG_REGISTERED. Just use it.
Signed-off-by: NYufen Yu <yuyufen@huawei.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

block/blk-iocost.c

@@ -669,7 +669,7 @@ static struct ioc *q_to_ioc(struct request_queue *q)
 
 static const char *q_name(struct request_queue *q)
 {
-	if (test_bit(QUEUE_FLAG_REGISTERED, &q->queue_flags))
+	if (blk_queue_registered(q))
 		return kobject_name(q->kobj.parent);
 	else
 		return "<unknown>";

block/elevator.c

@@ -672,7 +672,7 @@ void elevator_init_mq(struct request_queue *q)
 	if (!elv_support_iosched(q))
 		return;
 
-	WARN_ON_ONCE(test_bit(QUEUE_FLAG_REGISTERED, &q->queue_flags));
+	WARN_ON_ONCE(blk_queue_registered(q));
 
 	if (unlikely(q->elevator))
 		return;