w1 does not need to multicast its state to several groups at once,
and upcoming netlink changes will not allow bitmask for groups anyway.
Signed-off-by: Evgeniy Polyakov <johnpol@2ka.mipt.ru> Signed-off-by: Patrick McHardy <kaber@trash.net> Signed-off-by: David S. Miller <davem@davemloft.net>