AP_TECS: fixed compiler warning

- AP_Landing _landing was declared out-of-order

libraries/AP_TECS/AP_TECS.h

@@ -125,11 +125,11 @@ private:
     // reference to the AHRS object
     AP_AHRS &_ahrs;
 
+    const AP_Vehicle::FixedWing &aparm;
+
     // reference to const AP_Landing to access it's params
     const AP_Landing &_landing;
 
-    const AP_Vehicle::FixedWing &aparm;
-
     // TECS tuning parameters
     AP_Float _hgtCompFiltOmega;
     AP_Float _spdCompFiltOmega;