blk-mq: remove stale comment for blk_mq_sched_mark_restart_hctx

blk-mq: remove stale comment for blk_mq_sched_mark_restart_hctx

[ Upstream commit 4788ae11d2536f1211c49a02af40ccfad84b8858 ]

Commit 06391e05d8c2e ("blk-mq: remove synchronize_rcu() from
blk_mq_del_queue_tag_set()") remove handle of TAG_SHARED in restart,
then shared_hctx_restart counted for how many hardware queues are marked
for restart is removed too.
Remove the stale comment that we still count hardware queues need restart.

Fixes: 06391e05d8c2 ("blk-mq: remove synchronize_rcu() from blk_mq_del_queue_tag_set()")
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Kemeng Shi <shikemeng@huaweicloud.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>