arc: bluetooth: Implement Gatt notify

This patch does the following
- Implement the notification to arc bridge when remote
  Gatt characteristic value changed.
- Make Android request for writing to CCC Descriptor does
  nothing because Chrome bundle that to register/deregister
  for notification.

TEST=Test battery notification with Pixel C Keyboard

Signed-off-by: Puthikorn Voravootivat <>
Cr-Commit-Position: refs/heads/master@{#402331}
3 files changed