Update NRF52 build to work again

src/nrf52/NRF52Bluetooth.cpp

@@ -1,6 +1,7 @@
 #include "NRF52Bluetooth.h"
 #include "configuration.h"
 #include "main.h"
+#include "BluetoothCommon.h"
 #include <bluefruit.h>
 
 /* HRM Service Definitions
@@ -192,6 +193,11 @@ void NRF52Bluetooth::setup()
     }
 }
 
+/// Given a level between 0-100, update the BLE attribute
+void updateBatteryLevel(uint8_t level) {
+  // FIXME - implement
+}
+
 /*
 void loop()
 {