nvme: introduce nvme_check_ctrl_fabric_info helper

Inroduce nvme_check_ctrl_fabric_info helper to check fabric controller info
returned by target.

Signed-off-by: Guixin Liu <kanie@linux.alibaba.com>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Keith Busch <kbusch@kernel.org>