AC_AttitudeControlSub: fix update_althold_lean_angle_max use of throttle_in

libraries/AC_AttitudeControl/AC_AttitudeControl_Sub.cpp

@@ -267,7 +267,7 @@ void AC_AttitudeControl_Sub::update_althold_lean_angle_max(float throttle_in)
         return;
     }
 
-    float althold_lean_angle_max = acosf(constrain_float(_throttle_in/(AC_ATTITUDE_CONTROL_ANGLE_LIMIT_THROTTLE_MAX * thr_max), 0.0f, 1.0f));
+    float althold_lean_angle_max = acosf(constrain_float(throttle_in/(AC_ATTITUDE_CONTROL_ANGLE_LIMIT_THROTTLE_MAX * thr_max), 0.0f, 1.0f));
     _althold_lean_angle_max = _althold_lean_angle_max + (_dt/(_dt+_angle_limit_tc))*(althold_lean_angle_max-_althold_lean_angle_max);
 }