- fix compile error (again)
- fix compile error (again)

as per
https://devzone.nordicsemi.com/question/6950/upgrading-to-sdk-520-breaks
-build/?answer=14073#post-id-14073

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