blk-mq: delete dead struct blk_mq_hw_ctx->queued field

This counter is not used anywhere, so delete it.

Signed-off-by: Chengming Zhou <[e-mail]>
Reviewed-by: Bart Van Assche <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Jens Axboe <[e-mail]>

include/linux/blk-mq.h

···
 	 */
 	struct blk_mq_tags	*sched_tags;
 
-	/** @queued: Number of queued requests. */
-	unsigned long		queued;
 	/** @run: Number of dispatched requests. */
 	unsigned long		run;