msm: kgsl: Add support for Android's sync point framework

The Android sync point framework will replace the synchronization
previously implemented by genlock. This change implements the KGSL
component of the sync point framework by creating a fence that is
automatically signaled by KGSL when it's timestamp expires. The
fence FD is returned to the user driver so that another process
can wait for the sync point.

Change-Id: Ifee38dfde00e551f3524f7a37833938dcdb64905
Signed-off-by: Jeff Boody <jboody@codeaurora.org>