Sub: call compass cal routine directly from sched table

ArduSub/ArduSub.cpp

@@ -55,7 +55,7 @@ const AP_Scheduler::Task Sub::scheduler_tasks[] = {
 #if RPM_ENABLED == ENABLED
     SCHED_TASK(rpm_update,            10,    200),
 #endif
-    SCHED_TASK(compass_cal_update,   100,    100),
+    SCHED_TASK_CLASS(Compass,          &sub.compass,              cal_update, 100, 100),
     SCHED_TASK(accel_cal_update,      10,    100),
     SCHED_TASK(terrain_update,        10,    100),
 #if GRIPPER_ENABLED == ENABLED

ArduSub/Sub.h

@@ -455,7 +455,6 @@ private:
     static const struct LogStructure log_structure[];
 
     void init_compass_location();
-    void compass_cal_update(void);
     void fast_loop();
     void fifty_hz_loop();
     void update_batt_compass(void);

ArduSub/sensors.cpp

@@ -104,13 +104,6 @@ void Sub::init_optflow()
 }
 #endif      // OPTFLOW == ENABLED
 
-void Sub::compass_cal_update()
-{
-    if (!hal.util->get_soft_armed()) {
-        compass.compass_cal_update();
-    }
-}
-
 void Sub::accel_cal_update()
 {
     if (hal.util->get_soft_armed()) {