blk-mq: remove double set queue_num

hwctx's queue_num has been set prior call blk_mq_init_hctx, so no need
set it again.
Signed-off-by: Nweiping <zhangweiping@didichuxing.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>

block/blk-mq.c

@@ -1910,7 +1910,6 @@ static int blk_mq_init_hctx(struct request_queue *q,
 	spin_lock_init(&hctx->lock);
 	INIT_LIST_HEAD(&hctx->dispatch);
 	hctx->queue = q;
-	hctx->queue_num = hctx_idx;
 	hctx->flags = set->flags & ~BLK_MQ_F_TAG_SHARED;
 
 	cpuhp_state_add_instance_nocalls(CPUHP_BLK_MQ_DEAD, &hctx->cpuhp_dead);