AP_SmartRTL: use baro singleton

libraries/AP_SmartRTL/examples/SmartRTL_test/SmartRTL_test.cpp

@@ -21,9 +21,9 @@ static AP_SerialManager serial_manager;
 class DummyVehicle {
 public:
     RangeFinder rangefinder{serial_manager, ROTATION_PITCH_270};
-    NavEKF2 EKF2{&ahrs, barometer, rangefinder};
-    NavEKF3 EKF3{&ahrs, barometer, rangefinder};
-    AP_AHRS_NavEKF ahrs{ins, barometer, EKF2, EKF3, AP_AHRS_NavEKF::FLAG_ALWAYS_USE_EKF};
+    NavEKF2 EKF2{&ahrs, rangefinder};
+    NavEKF3 EKF3{&ahrs, rangefinder};
+    AP_AHRS_NavEKF ahrs{ins, EKF2, EKF3, AP_AHRS_NavEKF::FLAG_ALWAYS_USE_EKF};
 };
 
 static DummyVehicle vehicle;