[PATCH 2/9] nvme: use nvme_wait_ready in nvme_shutdown_ctrl

[Christoph Hellwig]

> One minor nit: I also notice that nvme_wait_ready busy loop sleeps for
> 1~2ms, while the existing shutdown code busy loop sleeps for 100ms. Though,
> I don't think it is an issue.

Thanks, I've added a note about that, and a reference to the commit
that changed from the msleep(100) to the usleep_range for the
enable/disable path.