block: remove redundant check about 'set->nr_hw_queues' in blk_mq_alloc_tag_set()

At the beginning of blk_mq_alloc_tag_set(), we have already checked whether
'set->nr_hw_queues' is zero, so here remove this redundant check.
Signed-off-by: NXiaoguang Wang <wangxg.fnst@cn.fujitsu.com>
Signed-off-by: NJens Axboe <axboe@fb.com>

block/blk-mq.c

@@ -2174,7 +2174,7 @@ int blk_mq_alloc_tag_set(struct blk_mq_tag_set *set)
 	if (set->queue_depth < set->reserved_tags + BLK_MQ_TAG_MIN)
 		return -EINVAL;
 
-	if (!set->nr_hw_queues || !set->ops->queue_rq || !set->ops->map_queue)
+	if (!set->ops->queue_rq || !set->ops->map_queue)
 		return -EINVAL;
 
 	if (set->queue_depth > BLK_MQ_MAX_DEPTH) {