ixgbe: updates vlan feature flags to enable FCoE offloads on vlan interface

Updates netdev->vlan_features for NETIF_F_FCOE_CRC and NETIF_F_FSO, so that
FCoE CRC and GSO offloads will get used for FCoE over ixgbe based vlan
interface.

Signed-off-by: Vasu Dev <vasu.dev@intel.com>
Signed-off-by: Yi Zou <yi.zou@intel.com>
Acked-by: Peter P Waskiewicz Jr <peter.p.waskiewicz.jr@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>