nvme: use nvme_wait_ready in nvme_shutdown_ctrl
Refactor the code to wait for CSTS state changes so that it can be reused
by nvme_shutdown_ctrl. This reduces the delay between each iteration
that checks CSTS from 100ms in the shutdown code to the 1 to 2ms range
done during enable, matching the changes from commit
3e98c2443f5c that
were only applied to the enable/disable path.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Keith Busch <kbusch@kernel.org>
Reviewed-by: Pankaj Raghav <p.raghav@samsung.com>