AP_FrSky_Telem: Make init return false if we failed to init

libraries/AP_Frsky_Telem/AP_Frsky_Telem.cpp

@@ -38,7 +38,7 @@ ObjectArray<mavlink_statustext_t> AP_Frsky_Telem::_statustext_queue(FRSKY_TELEM_
 /*
  * init - perform required initialisation
  */
-void AP_Frsky_Telem::init()
+bool AP_Frsky_Telem::init()
 {
     const AP_SerialManager &serial_manager = AP::serialmanager();
 
@@ -65,7 +65,11 @@ void AP_Frsky_Telem::init()
         hal.scheduler->register_io_process(FUNCTOR_BIND_MEMBER(&AP_Frsky_Telem::tick, void));
         // we don't want flow control for either protocol
         _port->set_flow_control(AP_HAL::UARTDriver::FLOW_CONTROL_DISABLE);
+
+        return true;
     }
+
+    return false;
 }
 
 

libraries/AP_Frsky_Telem/AP_Frsky_Telem.h

@@ -119,7 +119,7 @@ public:
     AP_Frsky_Telem &operator=(const AP_Frsky_Telem&) = delete;
 
     // init - perform required initialisation
-    void init();
+    bool init();
 
     // add statustext message to FrSky lib message queue
     void queue_message(MAV_SEVERITY severity, const char *text);