hwc: vpuclient: vpuClient implementation

Vpuclient is the client side for VFM in hwc. It follows the
similar pattern of prepare and draw. It has 2 step prepare
including: setVpuSession and prepare. The setVpuSession function
passes all the layers from the SF list to VFM, which marks
the layers that it can support. After this, the layer
allocation/configuration is done, and finally in prepare the
allocated pipes are passed down to VFM. The draw function
passes the handle to the VFM to draw the video layer.

Change-Id: I5d8795de35ed98716f7fa4cd48506b488cb3cb5d
diff --git a/libhwcomposer/hwc_utils.h b/libhwcomposer/hwc_utils.h
index 9ccfa1b..ce1abeb 100644
--- a/libhwcomposer/hwc_utils.h
+++ b/libhwcomposer/hwc_utils.h
@@ -145,6 +145,7 @@
 enum {
     HWC_MDPCOMP = 0x00000001,
     HWC_COPYBIT = 0x00000002,
+    HWC_VPUCOMP = 0x00000004,
 };
 
 // HAL specific features