net: 8139too: Initial necessary vlan_features to support vlan

Offload setting of vlan device requires
vlan_features to be initialized.
Signed-off-by: NShan Wei <shanwei@cn.fujitsu.com>
Acked-by: NFrancois Romieu <romieu@fr.zoreil.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

drivers/net/8139too.c

@@ -992,6 +992,7 @@ static int __devinit rtl8139_init_one (struct pci_dev *pdev,
 	 * features
 	 */
 	dev->features |= NETIF_F_SG | NETIF_F_HW_CSUM | NETIF_F_HIGHDMA;
+	dev->vlan_features = dev->features;
 
 	dev->irq = pdev->irq;