blk-mq: remove blk_mq_in_flight()

After commit 7be8356 ("block: fix that util can be greater than
100%"), it's not used and can be removed.

Link: https://lore.kernel.org/linux-raid/20250506124903.2540268-1-yukuai1@huaweicloud.com
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: John Garry <john.g.garry@oracle.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>

Author: YuKuai-huawei

block/blk-mq.c

@@ -101,16 +101,6 @@ static bool blk_mq_check_inflight(struct request *rq, void *priv)
 	return true;
 }
 
-unsigned int blk_mq_in_flight(struct request_queue *q,
-		struct block_device *part)
-{
-	struct mq_inflight mi = { .part = part };
-
-	blk_mq_queue_tag_busy_iter(q, blk_mq_check_inflight, &mi);
-
-	return mi.inflight[0] + mi.inflight[1];
-}
-
 void blk_mq_in_flight_rw(struct request_queue *q, struct block_device *part,
 		unsigned int inflight[2])
 {

block/blk-mq.h

@@ -246,8 +246,6 @@ static inline bool blk_mq_hw_queue_mapped(struct blk_mq_hw_ctx *hctx)
 	return hctx->nr_ctx && hctx->tags;
 }
 
-unsigned int blk_mq_in_flight(struct request_queue *q,
-		struct block_device *part);
 void blk_mq_in_flight_rw(struct request_queue *q, struct block_device *part,
 		unsigned int inflight[2]);