bridge: Add netlink interface to configure vlans on bridge ports

Add a netlink interface to add and remove vlan configuration on bridge port.
The interface uses the RTM_SETLINK message and encodes the vlan
configuration inside the IFLA_AF_SPEC.  It is possble to include multiple
vlans to either add or remove in a single message.

Signed-off-by: Vlad Yasevich <vyasevic@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/bridge/br_private.h b/net/bridge/br_private.h
index f0f2461..a42f9d4 100644
--- a/net/bridge/br_private.h
+++ b/net/bridge/br_private.h
@@ -713,6 +713,7 @@
 extern void br_netlink_fini(void);
 extern void br_ifinfo_notify(int event, struct net_bridge_port *port);
 extern int br_setlink(struct net_device *dev, struct nlmsghdr *nlmsg);
+extern int br_dellink(struct net_device *dev, struct nlmsghdr *nlmsg);
 extern int br_getlink(struct sk_buff *skb, u32 pid, u32 seq,
 		      struct net_device *dev);