nvme-multipath: do not reset on unknown status

The nvme multipath error handling defaults to controller reset if the
error is unknown. There are, however, no existing nvme status codes that
indicate a reset should be used, and resetting causes unnecessary
disruption to the rest of IO.

Change nvme's error handling to first check if failover should happen.
If not, let the normal error handling take over rather than reset the
controller.

Based-on-a-patch-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: John Meneghini <johnm@netapp.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>