- fix compile error
- fix compile error

https://devzone.nordicsemi.com/question/6950/upgrading-to-sdk-520-breaks
-build/

pi19404/arduino-BLEPeripheral,sandeepmistry/arduino-BLEPeripheral,possan/arduino-BLEPeripheral,femtoduino/arduino-BLEPeripheral,possan/arduino-BLEPeripheral,pi19404/arduino-BLEPeripheral,sandeepmistry/arduino-BLEPeripheral,femtoduino/arduino-BLEPeripheral,sandeepmistry/arduino-BLEPeripheral