fingerprint: notify client when cancelling succeeded

* Some fingerprint hardware hals might not notify userspace in time
  in some scenarios when successful authentication cancel is performed.
* This is observed for example in some devices that have power and/or home
  buttons merged with fingerprint sensor, but not limited to such cases.
* Add a opt-in configuration to enable client authentication cancel from
  fingerprint service when successful.
* This addresses originally an issue where requesting fingerprint to be
  disabled and then enabled will wait till cancelling timeout before changing
  fingerprint sensor state and start authenticating again.

Change-Id: I6a6795fbb795f0c6a4ff8ad27ac807e2f744c2d9
Signed-off-by: Carlo Savignano <carlosavignano@aospa.co>