net: make dev->master general

dev->master is now tightly connected to bonding driver. This patch makes
this pointer more general and ready to be used by others.

 - netdev_set_master() - bond specifics moved to new function
   netdev_set_bond_master()
 - introduced netif_is_bond_slave() to check if device is a bonding slave

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/infiniband/hw/nes/nes.c

@@ -153,7 +153,8 @@ static int nes_inetaddr_event(struct notifier_block *notifier,
 				nesdev, nesdev->netdev[0]->name);
 		netdev = nesdev->netdev[0];
 		nesvnic = netdev_priv(netdev);
-		is_bonded = (netdev->master == event_netdev);
+		is_bonded = netif_is_bond_slave(netdev) &&
+			    (netdev->master == event_netdev);
 		if ((netdev == event_netdev) || is_bonded) {
 			if (nesvnic->rdma_enabled == 0) {
 				nes_debug(NES_DBG_NETDEV, "Returning without processing event for %s since"