[SCSI] fcoe: Use LLD's WWPN and WWNN for lport if LLD supports ndo_fcoe_get_wwn

If the LLD wants its own WWNN/WWPN to be used, it should implement the
netdev_ops.ndo_fcoe_get_wwn(). If that is the case, we query the LLD and use
the queried WWNN/WWPN from the LLD.

Signed-off-by: Yi Zou <yi.zou@intel.com>
Signed-off-by: Robert Love <robert.w.love@intel.com>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>