bonding, ipv4, ipv6, vlan: Handle NETDEV_BONDING_FAILOVER like NETDEV_NOTIFY_PEERS

It is undesirable for the bonding driver to be poking into higher
level protocols, and notifiers provide a way to avoid that.  This does
mean removing the ability to configure reptitition of gratuitous ARPs
and unsolicited NAs.

Signed-off-by: Ben Hutchings <bhutchings@solarflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>