geofence_update.msg: notify navigator on geofence update

msg/CMakeLists.txt

@@ -59,6 +59,7 @@ set(msg_file_names
 	follow_target.msg
 	fw_pos_ctrl_status.msg
 	geofence_result.msg
+	geofence_update.msg
 	gps_dump.msg
 	gps_inject_data.msg
 	hil_sensor.msg

msg/geofence_update.msg

@@ -0,0 +1,4 @@
+# This message is used to notify the system about a geofence update (dataman
+# storage)
+
+uint32 dummy       # unused