ide: don't acquire queue lock in ide_pm_execute_rq

There is nothing we can synchronize against over a call to
blk_queue_dying.

Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>