Copter: move set_throttle_takeoff implementation into Mode

No callers except the mode objects, so move it.

ArduCopter/Attitude.cpp

@@ -69,13 +69,6 @@ void Copter::update_throttle_hover()
 #endif
 }
 
-// set_throttle_takeoff - allows parents to tell throttle controller we are taking off so I terms can be cleared
-void Copter::set_throttle_takeoff()
-{
-    // tell position controller to reset alt target and reset I terms
-    pos_control->init_takeoff();
-}
-
 // get_pilot_desired_climb_rate - transform pilot's throttle input to climb rate in cm/s
 // without any deadzone at the bottom
 float Copter::get_pilot_desired_climb_rate(float throttle_control)

ArduCopter/Copter.h

@@ -661,7 +661,6 @@ private:
     // Attitude.cpp
     float get_pilot_desired_yaw_rate(int16_t stick_angle);
     void update_throttle_hover();
-    void set_throttle_takeoff();
     float get_pilot_desired_climb_rate(float throttle_control);
     float get_non_takeoff_throttle();
     float get_avoidance_adjusted_climbrate(float target_rate);

ArduCopter/mode.cpp

@@ -796,9 +796,12 @@ GCS_Copter &Mode::gcs()
     return copter.gcs();
 }
 
+// set_throttle_takeoff - allows modes to tell throttle controller we
+// are taking off so I terms can be cleared
 void Mode::set_throttle_takeoff()
 {
-    return copter.set_throttle_takeoff();
+    // tell position controller to reset alt target and reset I terms
+    pos_control->init_takeoff();
 }
 
 float Mode::get_avoidance_adjusted_climbrate(float target_rate)

ArduCopter/takeoff.cpp

@@ -54,7 +54,7 @@ void Mode::_TakeOff::start(float alt_cm)
     // indicate we are taking off
     copter.set_land_complete(false);
     // tell position controller to reset alt target and reset I terms
-    copter.set_throttle_takeoff();
+    copter.flightmode->set_throttle_takeoff();
 
     // calculate climb rate
     const float speed = MIN(copter.wp_nav->get_default_speed_up(), MAX(copter.g.pilot_speed_up*2.0f/3.0f, copter.g.pilot_speed_up-50.0f));