nvme-fc: use separate work queue to avoid warning

nvme-fc: use separate work queue to avoid warning

[ Upstream commit 8730c1ddb69bdeeb10c1f613a4e15e95862b1981 ]

When tearing down a controller the following warning is issued:

WARNING: CPU: 0 PID: 30681 at ../kernel/workqueue.c:2418 check_flush_dependency

This happens as the err_work workqueue item is scheduled on the
system workqueue (which has WQ_MEM_RECLAIM not set), but is flushed
from a workqueue which has WQ_MEM_RECLAIM set.

Fix this by providing an FC-NVMe specific workqueue.

Fixes: 4cff280a5fcc ("nvme-fc: resolve io failures during connect")
Signed-off-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: James Smart <james.smart@broadcom.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sasha Levin <sashal@kernel.org>