Fixed a bug related to render sync fd.

Fixed a bug related to render sync fd.

 - Very occasionally, when twe_thread is pushed down by scheduling,
  a sync_fd cannot be attached to twe_thread.
 - In this case, queue_can_acquire and render_done_cnt are different
  and the commit is delayed by one frame.
 - This problem may cause can_dequeue_timeout
  depending on the hwc situation.
 - Even if queue_flush is performed after can_dequeue_timeout,
  the commit latency cannot be restored until another interrupt occurs.

Change-Id: I32bc48d523e815a944cbfb935277adc1bcc2bf44
Signed-off-by: Joonbum Ko <joonbum.ko@samsung.com>