wl_egl: Implement status_sync to improve buffers finalize logic.

wl_egl: Implement status_sync to improve buffers finalize logic.

AS-IS
- When wl_egl_display->thread is idle, call the __idle_cb_buffers_finalize() to check the buffer status and change the buffer status to RELEASED.
- If the buffer status cannot be changed to RELEASED, continue to call the function until possible.
PROBLEMS
- Call the function even if the buffer status has not changed. So the function is unnecessarily called a lot.
TO-BE
- Call the function only when the buffer status changes.

Change-Id: I76d401a1413d144dcde2e4743162d9a09bc86983