mc_att_control: use attitude timestamp for dt

src/modules/mc_att_control/mc_att_control_main.cpp

@@ -287,10 +287,10 @@ MulticopterAttitudeControl::Run()
 			_attitude_control.adaptAttitudeSetpoint(delta_q_reset);
 		}
 
-		const hrt_abstime now = hrt_absolute_time();
+		const hrt_abstime now = _v_att.timestamp;
 
 		// Guard against too small (< 0.2ms) and too large (> 20ms) dt's.
-		const float dt = math::constrain(((now - _last_run) / 1e6f), 0.0002f, 0.02f);
+		const float dt = math::constrain(((now - _last_run) * 1e-6f), 0.0002f, 0.02f);
 		_last_run = now;
 
 		/* check for updates in other topics */