transfox: fix set/get_freq by setting current vfo

kenwood/transfox.c

@@ -170,6 +170,8 @@ int transfox_open(RIG *rig)
 {
 	rig_debug(RIG_DEBUG_TRACE, "%s called\n", __func__);
 
+	rig->state.current_vfo = RIG_VFO_A;
+
 	/* do not call kenwood_open(rig), rig has no "ID" command */
 
 	return RIG_OK;