nvme-fcloop: add target to host LS request support

Add support for performing LS requests from target to host.
Include sending request from targetport, reception into host,
host sending ls rsp.

Signed-off-by: James Smart <jsmart2021@gmail.com>
Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>