nvme: Fix locking protocol violation to fix suspend / resume

Currently, when we suspend, we need to tear down all the qpairs. We call
nvme_admin_qpair_abort_aers with the admin qpair lock held, but the
tracker it will call for the pending AER also locks it (recursively)
hitting an assert. This routine is called without the qpair lock held
when we destroy the device entirely in a number of places. Add an assert
to this effect and drop the qpair lock before calling it.
nvme_admin_qpair_abort_aers then locks the qpair lock to traverse the
list, dropping it around calls to nvme_qpair_complete_tracker, and
restarting the list scan after picking it back up.

Note: If interrupts are still running, there's a tiny window for these
AERs: If one fires just an instant after we manually complete it, then
we'll be fine: we set the state of the queue to 'waiting' and we ignore
interrupts while 'waiting'. We know we'll destroy all the queue state
with these pending interrupts before looking at them again and we know
all the TRs will have been completed or rescheduled. So either way we're
covered.

Also, tidy up the failure case as well: failing a queue is a superset of
disabling it, so no need to call disable first. This solves solves some
locking issues with recursion since we don't need to recurse.. Set the
qpair state of failed queues to RECOVERY_FAILED and stop scheduling the
watchdog. Assert we're not failed when we're enabling a qpair, since
failure currently is one-way. Make failure a little less verbose.

Next, kill the pre/post reset stuff. It's completely bogus since we
disable the qparis, we don't need to also hold the lock through the
reset: disabling will cause the ISR to return early. This keeps us from
recursing on the recovery lock when resuming. We only need the recovery
lock to avoid a specific race between the timer and the ISR.

Finally, kill NVME_RESET_2X. It'S been a major release since we put it
in and nobody has used it as far as I can tell. And it was a motivator
for the pre/post uglification.

These are all interrelated, so need to be done at the same time.

Sponsored by:		Netflix
Reviewed by:		jhb
Tested by:		jhb (made sure suspend / resume worked)
MFC After:		3 days
Differential Revision:	https://reviews.freebsd.org/D41866

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