scsi: qedf: Set WWNN and WWPN based on values from qed.

If dev_info.wwpn and dev_info.wwnn are set by qed use these values to set
the WWNs of the port. Otherwise fall back to the old method using
fcoe_wwn_from_mac().

Signed-off-by: Chad Dupuis <chad.dupuis@cavium.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>