AP_Generator: adapt to upstream mavlink changes

libraries/AP_Generator/AP_Generator_RichenPower.cpp

@@ -374,7 +374,9 @@ void AP_Generator_RichenPower::send_generator_status(const GCS_MAVLINK &channel)
         last_reading.output_voltage, // bus_voltage; Voltage of the bus seen at the generator
         INT16_MAX, // rectifier_temperature
         std::numeric_limits<double>::quiet_NaN(), // bat_current_setpoint; The target battery current
-        INT16_MAX // generator temperature
+        INT16_MAX, // generator temperature
+        UINT32_MAX, // seconds this generator has run since it was rebooted
+        INT32_MAX // seconds until this generator requires maintenance
         );
 }