blk-mq: remove useless checking in queue_requests_store()

blk_mq_queue_attr_visible() already checked queue_is_mq(), no need to
check this again in queue_requests_store().

Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-sysfs.c

@@ -69,9 +69,6 @@ queue_requests_store(struct gendisk *disk, const char *page, size_t count)
 	unsigned int memflags;
 	struct request_queue *q = disk->queue;
 
-	if (!queue_is_mq(q))
-		return -EINVAL;
-
 	ret = queue_var_store(&nr, page, count);
 	if (ret < 0)
 		return ret;