CameraHal: Various AF related fixes

- In case of AF timeout the focus callback was being
  disabled. This callback will not get re-enabled
  again until preview is restarted.
- Cancel AF is not working properly. Depending on the
  timing the off status event might not reach 'doAutoFocus()'.
- This change also replaces the 'mDoAFSem' semaphore with
  a condition variable.

Change-Id: I2ab7d87a05d97435aa6e67a122cc37a975794fc2
Signed-off-by: Emilian Peev <epeev@mm-sol.com>
3 files changed