AP_Notify: disable buzzer along with external leds

libraries/AP_Notify/Buzzer.cpp

@@ -23,8 +23,13 @@
 
 extern const AP_HAL::HAL& hal;
 
-bool Buzzer::init()
+void Buzzer::init()
 {
+    // return immediately if disabled
+    if (!AP_Notify::flags.external_leds) {
+        return;
+    }
+
     // setup the pin and ensure it's off
     hal.gpio->pinMode(BUZZER_PIN, GPIO_OUTPUT);
     on(false);
@@ -33,12 +38,16 @@ bool Buzzer::init()
     // warning in plane and rover on every boot
     _flags.armed = AP_Notify::flags.armed;
     _flags.failsafe_battery = AP_Notify::flags.failsafe_battery;
-    return true;
 }
 
 // update - updates led according to timed_updated.  Should be called at 50Hz
 void Buzzer::update()
 {
+    // return immediately if disabled
+    if (!AP_Notify::flags.external_leds) {
+        return;
+    }
+
     // reduce 50hz call down to 10hz
     _counter++;
     if (_counter < 5) {

libraries/AP_Notify/Buzzer.h

@@ -22,6 +22,8 @@
 # define BUZZER_PIN     63      // pin 63 on APM1
 #elif CONFIG_HAL_BOARD == HAL_BOARD_APM2
  # define BUZZER_PIN    59      // pin 59 on APM2
+#else
+ # define BUZZER_PIN    0       // pin undefined on other boards
 #endif
 
 class Buzzer
@@ -31,7 +33,7 @@ public:
     Buzzer() : _counter(0), _pattern(NONE), _pattern_counter(0) {}
 
     /// init - initialise the buzzer
-    bool init(void);
+    void init(void);
 
     /// update - updates buzzer according to timed_updated.  Should be called at 50Hz
     void update();