Fix Simulator: Set correct rotor count for standard VTOL

The rotor count was incorrect which meant that control surfaces like elevons were scaled incorrectly. This was the main reason for really bad SITL performance

src/modules/simulator/simulator_mavlink.cpp

@@ -113,7 +113,8 @@ void Simulator::pack_actuator_message(mavlink_hil_actuator_controls_t &msg, unsi
 			break;
 
 		case MAV_TYPE_VTOL_RESERVED2:
-			n = 8;
+			// this is the standard VTOL / quad plane with 5 propellers
+			n = 5;
 			break;
 
 		default: