net: bonding: Issue NETDEV_PRE_CHANGEADDR

Give interested parties an opportunity to veto an impending HW address
change.

Signed-off-by: Petr Machata <petrm@mellanox.com>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Reviewed-by: Ido Schimmel <idosch@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>