GFX-Display: updated overlay wait for vblank to use blocked waiting instead of queryi...

GFX-Display: updated overlay wait for vblank to use blocked waiting instead of querying it in a busy loop

BZ: 18446

This patch 1/3 for flicking issue on overlay while video playback.
we need wait for vblank to make sure overlay has been switch to
a buffer successfully, or the buffer consumed by overlay might be
dequeued by video driver override the buffer data while overlay
is fetching data. Perviously, wait for vblank was implemented as
a busy loop which is ineffient and power consuming.

This patch reimplemented the overlay wait for vblank as a blocking
waiting, so that OS will put the caller thread to sleep while waiting
for vblank.

Change-Id: I29de9c12155cb0b2b60945e47dd675174bb52717
Signed-off-by: Jackie Li <yaodong.li@intel.com>
Reviewed-on: http://android.intel.com:8080/35165
Reviewed-by: Ding, Haitao <haitao.ding@intel.com>
Tested-by: Ding, Haitao <haitao.ding@intel.com>
Reviewed-by: buildbot <buildbot@intel.com>
Tested-by: buildbot <buildbot@intel.com>