block: don't quiesce queue for calling elevator_set_none()

blk_mq_freeze_queue() can't be called on quiesced queue, otherwise it may
never return if there is any queued requests.

Fix it by removing quiesce queue around elevator_set_none() because
elevator_switch() does quiesce queue in case that we need to switch
to none really.

Fixes: 1e44bedb ("block: unifying elevator change")
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Link: https://lore.kernel.org/r/20250508085807.3175112-2-ming.lei@redhat.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>