ixgbe: Add support for netdev_ops.ndo_fcoe_get_wwn to 82599

Implements the netdev_ops.ndo_fcoe_get_wwn in 82599 if it finds valid
prefix for the World Wide Node Name (WWNN) or World Wide Port Name (WWPN),
as well as valid SAN MAC address.

Signed-off-by: Yi Zou <yi.zou@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>