Rover: move automatic declination setting into AP_Compass itself

APMrover2/Rover.cpp

@@ -283,9 +283,6 @@ void Rover::one_second_loop(void)
         update_home();
     }
 
-    // init compass location for declination
-    init_compass_location();
-
     // update error mask of sensors and subsystems. The mask uses the
     // MAV_SYS_STATUS_* values from mavlink. If a bit is set then it
     // indicates that the sensor or subsystem is present but not

APMrover2/Rover.h

@@ -423,7 +423,6 @@ private:
     bool trim_radio();
 
     // sensors.cpp
-    void init_compass_location(void);
     void update_compass(void);
     void compass_save(void);
     void init_beacon();

APMrover2/sensors.cpp

@@ -3,21 +3,6 @@
 #include <AP_RangeFinder/RangeFinder_Backend.h>
 #include <AP_VisualOdom/AP_VisualOdom.h>
 
-/*
-  initialise compass's location used for declination
- */
-void Rover::init_compass_location(void)
-{
-    // update initial location used for declination
-    if (!compass_init_location) {
-        Location loc;
-        if (ahrs.get_position(loc)) {
-            compass.set_initial_location(loc.lat, loc.lng);
-            compass_init_location = true;
-        }
-    }
-}
-
 // check for new compass data - 10Hz
 void Rover::update_compass(void)
 {