block: Remove unused member (busy) from struct blk_queue_tag

Signed-off-by: Ritesh Harjani <riteshh@codeaurora.org>
Reviewed-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Jens Axboe <axboe@fb.com>

include/linux/blkdev.h

@@ -288,7 +288,6 @@ enum blk_queue_state {
 struct blk_queue_tag {
 	struct request **tag_index;	/* map of busy tags */
 	unsigned long *tag_map;		/* bit map of free/busy tags */
-	int busy;			/* current depth */
 	int max_depth;			/* what we will send to device */
 	int real_max_depth;		/* what the array can hold */
 	atomic_t refcnt;		/* map can be shared */