Plane: call compass cal routine directly from sched table

ArduPlane/ArduPlane.cpp

@@ -59,7 +59,7 @@ const AP_Scheduler::Task Plane::scheduler_tasks[] = {
     SCHED_TASK_CLASS(AP_Notify,      &plane.notify,  update, 50, 300),
     SCHED_TASK(read_rangefinder,       50,    100),
     SCHED_TASK_CLASS(AP_ICEngine, &plane.g2.ice_control, update, 10, 100),
-    SCHED_TASK(compass_cal_update,     50,    50),
+    SCHED_TASK_CLASS(Compass,          &plane.compass,              cal_update, 50, 50),
     SCHED_TASK(accel_cal_update,       10,    50),
 #if OPTFLOW == ENABLED
     SCHED_TASK_CLASS(OpticalFlow, &plane.optflow, update,    50,    50),

ArduPlane/Plane.h

@@ -966,7 +966,6 @@ private:
 #if ADVANCED_FAILSAFE == ENABLED
     void afs_fs_check(void);
 #endif
-    void compass_cal_update();
     void update_optical_flow(void);
     void one_second_loop(void);
     void airspeed_ratio_update(void);

ArduPlane/sensors.cpp

@@ -38,15 +38,6 @@ void Plane::read_rangefinder(void)
     rangefinder_height_update();
 }
 
-/*
-  calibrate compass
-*/
-void Plane::compass_cal_update() {
-    if (!hal.util->get_soft_armed()) {
-        compass.compass_cal_update();
-    }
-}
-
 /*
     Accel calibration
 */