android: convert sync to fence api, v6

Just to show it's easy.

Android syncpoints can be mapped to a timeline. This removes the need
to maintain a separate api for synchronization. I've left the android
trace events in place, but the core fence events should already be
sufficient for debugging.

v2:
- Call fence_remove_callback in sync_fence_free if not all fences have fired.
v3:
- Merge Colin Cross' bugfixes, and the android fence merge optimization.
v4:
- Merge with the upstream fixes.
v5:
- Fix small style issues pointed out by Thomas Hellstrom.
v6:
- Fix for updates to fence api.

Signed-off-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Acked-by: John Stultz <john.stultz@linaro.org>
Acked-by: Sumit Semwal <sumit.semwal@linaro.org>
Acked-by: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>