OMAPFB: Asynchronous vsync notification

Enabled and disabled through new OMAPFB_ENABLEVSYNC ioctl.  Events delivered
as switch events.

Picked from :
https://android-review.googlesource.com/#/c/38924/

Change-Id: I0c431398030074e39a896e62df47727ae3d2c183
Signed-off-by: Vishal Bhoj <vishal.bhoj@linaro.org>
4 files changed