w1: reply only to the requester portid

Unicast one wire replies back to the sender portid to avoid multiple
programs getting each other's messages, especially as the response
can't be uniquely identified with the sequence coming from the
requesting program when both programs generate the same id.  Continue
to broadcast events such as add/remove master/slave devices.

Signed-off-by: David Fries <David@Fries.net>
Acked-by: Evgeniy Polyakov <zbr@ioremap.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>