netdev: update frequency on channel switch events

While we correctly emit a NETDEV_EVENT_CHANNEL_SWITCHED event from
netdev for other modules to respond to, we fail to actually update the
frequency of the netdev object in question. Since the netdev frequency
is used elsewhere (e.g. to send action frames), it needs updating too.

Fixes: 5eb0b7ca8e ("netdev: add a channel switch event")

src/netdev.c

@@ -4710,6 +4710,8 @@ static void netdev_channel_switch_event(struct l_genl_msg *msg,
 
 	l_debug("Channel switch event, frequency: %u", *freq);
 
+	netdev->frequency = *freq;
+
 	if (!netdev->event_filter)
 		return;