camera: Fix the flash sync issue in CAF mode

Fix the sync issue between snapshot and flash
in CAF mode.
This is still not an ideal solution, but at least
it doesn't generate black photos anymore

Change-Id: Iccb84c2a00c8b891a8c57c72aa77d970af00bbed
Merge remote-tracking branch 'upstream/cm-10.2' into dark-jelly-cm-10.2