net: add netif_is_lag_port helper

BugLink: http://bugs.launchpad.net/bugs/1562310

Some code does not mind if a device is bond slave or team port and treats
them the same, as generic LAG ports.
Signed-off-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit e0ba1414)
Signed-off-by: Tim Gardner <tim.gardner@canonical.com>

include/linux/netdevice.h

@@ -3904,6 +3904,11 @@ static inline bool netif_is_lag_master(struct net_device *dev)
 	return netif_is_bond_master(dev) || netif_is_team_master(dev);
 }
 
+static inline bool netif_is_lag_port(struct net_device *dev)
+{
+	return netif_is_bond_slave(dev) || netif_is_team_port(dev);
+}
+
 /* This device needs to keep skb dst for qdisc enqueue or ndo_start_xmit() */
 static inline void netif_keep_dst(struct net_device *dev)
 {