net: vlan: announce STAG offload capability in some drivers

- macvlan: propagate STAG filtering capabilities from underlying device
- ifb: announce STAG tagging support in addition to CTAG tagging support
- veth: announce STAG tagging/stripping support in addition to CTAG support

Signed-off-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/ifb.c b/drivers/net/ifb.c
index 724ce7a..dc9f6a4 100644
--- a/drivers/net/ifb.c
+++ b/drivers/net/ifb.c
@@ -166,7 +166,8 @@
 
 #define IFB_FEATURES (NETIF_F_HW_CSUM | NETIF_F_SG  | NETIF_F_FRAGLIST	| \
 		      NETIF_F_TSO_ECN | NETIF_F_TSO | NETIF_F_TSO6	| \
-		      NETIF_F_HIGHDMA | NETIF_F_HW_VLAN_CTAG_TX)
+		      NETIF_F_HIGHDMA | NETIF_F_HW_VLAN_CTAG_TX		| \
+		      NETIF_F_HW_VLAN_STAG_TX)
 
 static void ifb_setup(struct net_device *dev)
 {