In order to support all three modes of macvlan at
runtime, extend the existing netlink protocol
to allow choosing the mode per macvlan slave
interface.

This depends on a matching patch to iproute2
in order to become accessible in user land.
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Patrick McHardy <kaber@trash.net>
Signed-off-by: David S. Miller <davem@davemloft.net>