nvme-fc: don't bother to validate ioccsz and iorcsz

Discovery controllers don't set the values. They are in reserved
areas of the Identify Controller data structure.

Given the cmd completed, the minimal capsule sizes are supported,
so no need to check nqn to detect discovery controllers and
special case validations.

Signed-off-by: James Smart <james.smart@broadcom.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Sagi Grimberg <sagi@grimberg.me>
Signed-off-by: Jens Axboe <axboe@fb.com>