Replace VSYNC uevent thread with a custom IOCTL.

* The uevents were causing high CPU usage in android
  system_server for really no good reason since it
  doesn't need to watch for them




  8e68584




Change-Id: Ia5dd0b5f33e10cc63f96117e94c08dfc40cf5824




Signed-off-by: stratosk <stratosk@semaphore.gr>