blk-mq: add blk_mq_stop_hw_queues

Add a helper to iterate over all hw queues and stop them.  This is useful
for driver that implement PM suspend functionality.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Modified to just call blk_mq_stop_hw_queue() by Jens.

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

diff --cc block/blk-mq.c
Simple merge

diff --cc include/linux/blk-mq.h
Simple merge