Sub: let AHRS update orientation in its own time

ArduSub/ArduSub.cpp

@@ -269,9 +269,6 @@ void Sub::one_hz_loop()
     }
 
     if (!motors.armed()) {
-        // make it possible to change ahrs orientation at runtime during initial config
-        ahrs.update_orientation();
-
         motors.update_throttle_range();
     }