microbit: HOTFIX: BLE Notification bug in MicroBitDFUService
microbit: HOTFIX: BLE Notification bug in MicroBitDFUService

Hotfix of a minor bug in the MicroBitDFU Service that prevented BLE notifications
from being sent on the FlashCode characterisitic. Needed as the Samsung companion
app is dependent on this functionality to enable BLE programmming of the micro:bit.

markshannon/microbit-dal,markshannon/microbit-dal