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>

drivers/w1/w1.h

@@ -210,6 +210,11 @@ struct w1_master
 	struct w1_bus_master	*bus_master;
 
 	u32			seq;
+	/* port id to send netlink responses to.  The value is temporarily
+	 * stored here while processing a message, set after locking the
+	 * mutex, zero before unlocking the mutex.
+	 */
+	u32			portid;
 };
 
 /**