nvme-pci: fix hot removal during error handling

A removal waits for the reset_work to complete. If a surprise removal
occurs around the same time as an error triggered controller reset, and
reset work happened to dispatch a command to the removed controller, the
command won't be recovered since the timeout work doesn't do anything
during error recovery. We wouldn't want to wait for timeout handling
anyway, so this patch fixes this by disabling the controller and killing
admin queues prior to syncing with the reset_work.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Christoph Hellwig <hch@lst.de>