SurfaceFlinger: remove a driver bug workaround

Change-Id: I7478293e87899d6e467db8c2f9e295935c8b1d4e
diff --git a/services/surfaceflinger/Layer.cpp b/services/surfaceflinger/Layer.cpp
index f94a9ba..0cc03e1 100644
--- a/services/surfaceflinger/Layer.cpp
+++ b/services/surfaceflinger/Layer.cpp
@@ -539,9 +539,6 @@
 
         const HWComposer& hwc = mFlinger->getHwComposer();
         sp<Fence> presentFence = hwc.getDisplayFence(HWC_DISPLAY_PRIMARY);
-        // XXX: Temporarily don't use the present fence from HWC to work
-        // around a driver bug.
-        presentFence.clear();
         if (presentFence != NULL) {
             mFrameTracker.setActualPresentFence(presentFence);
         } else {