mc_att_control: don't keep att copy and avoid unnecessary Quatf construction and copies

src/modules/mc_att_control/AttitudeControl/AttitudeControl.cpp

@@ -52,12 +52,11 @@ void AttitudeControl::setProportionalGain(const matrix::Vector3f &proportional_g
 	}
 }
 
-matrix::Vector3f AttitudeControl::update(matrix::Quatf q) const
+matrix::Vector3f AttitudeControl::update(const Quatf &q) const
 {
 	Quatf qd = _attitude_setpoint_q;
 
 	// ensure input quaternions are exactly normalized because acosf(1.00001) == NaN
-	q.normalize();
 	qd.normalize();
 
 	// calculate reduced desired attitude neglecting vehicle's yaw to prioritize roll and pitch

src/modules/mc_att_control/AttitudeControl/AttitudeControl.hpp

@@ -89,7 +89,7 @@ public:
 	 * @param q estimation of the current vehicle attitude unit quaternion
 	 * @return [rad/s] body frame 3D angular rate setpoint vector to be executed by the rate controller
 	 */
-	matrix::Vector3f update(matrix::Quatf q) const;
+	matrix::Vector3f update(const matrix::Quatf &q) const;
 
 private:
 	matrix::Vector3f _proportional_gain;