Tracker: remove usb-mux checking

AntennaTracker/AntennaTracker.cpp

@@ -49,7 +49,6 @@ const AP_Scheduler::Task Tracker::scheduler_tasks[] = {
 #endif
     SCHED_TASK_CLASS(AP_InertialSensor, &tracker.ins,       periodic,       50,   50),
     SCHED_TASK_CLASS(AP_Notify,         &tracker.notify,    update,         50,  100),
-    SCHED_TASK(check_usb_mux,          10,    300),
     SCHED_TASK(gcs_retry_deferred,     50,   1000),
     SCHED_TASK(one_second_loop,         1,   3900),
     SCHED_TASK(compass_cal_update,     50,    100),

AntennaTracker/Tracker.h

@@ -100,8 +100,6 @@ private:
 
     uint32_t start_time_ms = 0;
 
-    bool usb_connected = false;
-
     DataFlash_Class DataFlash;
 
     AP_GPS gps;
@@ -236,7 +234,6 @@ private:
     void disarm_servos();
     void prepare_servos();
     void set_mode(enum ControlMode mode, mode_reason_t reason);
-    void check_usb_mux(void);
     void update_vehicle_pos_estimate();
     void update_tracker_position();
     void update_bearing_and_distance();

AntennaTracker/system.cpp

@@ -49,11 +49,6 @@ void Tracker::init_tracker()
     barometer.set_log_baro_bit(MASK_LOG_IMU);
     barometer.init();
 
-    // we start by assuming USB connected, as we initialed the serial
-    // port with SERIAL0_BAUD. check_usb_mux() fixes this if need be.    
-    usb_connected = true;
-    check_usb_mux();
-
     // setup telem slots with serial ports
     gcs().setup_uarts(serial_manager);
 
@@ -219,17 +214,6 @@ void Tracker::set_mode(enum ControlMode mode, mode_reason_t reason)
 	DataFlash.Log_Write_Mode(control_mode, reason);
 }
 
-void Tracker::check_usb_mux(void)
-{
-    bool usb_check = hal.gpio->usb_connected();
-    if (usb_check == usb_connected) {
-        return;
-    }
-
-    // the user has switched to/from the telemetry port
-    usb_connected = usb_check;
-}
-
 /*
   should we log a message type now?
  */