ArduCopter: use AP::compass().available in place of enabled()

ArduCopter/Copter.cpp

@@ -380,7 +380,7 @@ void Copter::update_batt_compass(void)
     // read battery before compass because it may be used for motor interference compensation
     battery.read();
 
-    if(AP::compass().enabled()) {
+    if(AP::compass().available()) {
         // update compass with throttle value - used for compassmot
         compass.set_throttle(motors->get_throttle());
         compass.set_voltage(battery.voltage());

ArduCopter/compassmot.cpp

@@ -34,7 +34,7 @@ MAV_RESULT Copter::mavlink_compassmot(const GCS_MAVLINK &gcs_chan)
     }
 
     // check compass is enabled
-    if (!AP::compass().enabled()) {
+    if (!AP::compass().available()) {
         gcs_chan.send_text(MAV_SEVERITY_CRITICAL, "Compass disabled");
         ap.compass_mot = false;
         return MAV_RESULT_TEMPORARILY_REJECTED;