nvme: sync timeout work on failed reset

Timeouts during reset will set the controller for failure, preventing
the state change to LIVE. Ensure all timeout work is synced after the
controller disabling completes to ensure we don't have any other tasks
messing with any namespace request_queue's.

Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>