Looking for review / testing for nvme suspend / resume support

[Warner Losh]

I've posted a review: https://reviews.freebsd.org/D21493 for NVMe suspend /
resume support. This avoids issues where we come out of suspend and need to
wait 30s for there to be a timeout and a reset of the device. It does so by
completely shutting down the card before we suspend, and then assume it was
in an unknown state when we come back up.

Please leave comments about successful (or unsuccessful) tests and/or ways
to improve the code.

Thanks!

Warner