Disable "MANUAL_CONTROL" warning message for ArduSub, which supports it.

src/FlightDisplay/FlightDisplayView.qml

@@ -91,7 +91,7 @@ QGCView {
     }
 
     function px4JoystickCheck() {
-        if (_activeVehicle && !_activeVehicle.px4Firmware && (QGroundControl.virtualTabletJoystick || _activeVehicle.joystickEnabled)) {
+        if ( _activeVehicle && !_activeVehicle.supportsManualControl && (QGroundControl.virtualTabletJoystick || _activeVehicle.joystickEnabled)) {
             px4JoystickSupport.open()
         }
     }

src/Vehicle/Vehicle.cc

@@ -1505,6 +1505,19 @@ bool Vehicle::vtol(void) const
     }
 }
 
+bool Vehicle::supportsManualControl(void) const
+{
+    // PX4 Firmware supports manual control message
+    if ( px4Firmware() ) {
+        return true;
+    }
+    // ArduSub supports manual control message (identified by APM + Submarine type)
+    if ( apmFirmware() && vehicleType() == MAV_TYPE_SUBMARINE ) {
+        return true;
+    }
+    return false;
+}
+
 void Vehicle::_setCoordinateValid(bool coordinateValid)
 {
     if (coordinateValid != _coordinateValid) {

src/Vehicle/Vehicle.h

@@ -275,6 +275,7 @@ public:
     Q_PROPERTY(bool                 multiRotor              READ multiRotor                                             CONSTANT)
     Q_PROPERTY(bool                 vtol                    READ vtol                                                   CONSTANT)
     Q_PROPERTY(bool                 rover                   READ rover                                                  CONSTANT)
+    Q_PROPERTY(bool                 supportsManualControl   READ supportsManualControl                                  CONSTANT)
     Q_PROPERTY(bool                 autoDisconnect          MEMBER _autoDisconnect                                      NOTIFY autoDisconnectChanged)
     Q_PROPERTY(QString              prearmError             READ prearmError            WRITE setPrearmError            NOTIFY prearmErrorChanged)
     Q_PROPERTY(int                  motorCount              READ motorCount                                             CONSTANT)
@@ -466,6 +467,8 @@ public:
     bool vtol(void) const;
     bool rover(void) const;
 
+    bool supportsManualControl(void) const;
+
     void setFlying(bool flying);
     void setGuidedMode(bool guidedMode);