AP_OpticalFlow: apply yaw for flow in all drivers

libraries/AP_OpticalFlow/AP_OpticalFlow_Onboard.cpp

@@ -77,6 +77,8 @@ void AP_OpticalFlow_Onboard::update()
 
         state.bodyRate.y = 1.0f / float(data_frame.delta_time) *
                            data_frame.gyro_y_integral;
+
+        _applyYaw(state.flowRate);
     } else {
         state.flowRate.zero();
         state.bodyRate.zero();

libraries/AP_OpticalFlow/AP_OpticalFlow_SITL.cpp

@@ -117,6 +117,8 @@ void AP_OpticalFlow_SITL::update(void)
         }
     }
 
+    _applyYaw(state.flowRate);
+    
     // copy results to front end
     _update_frontend(state);
 }