NVMe always completes the request before returning from ->timeout, either
by polling for it, or by disabling the controller. Return BLK_EH_DONE so
that the block layer doesn't even try to complete it again.
Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>