hwc: Add support for plane alpha

HWC 1.2 API passes down the plane alpha and the blending
operation to apply. Pass this information to the MDP.

Change-Id: I7fbd17345d9157aa654e4b1031ac3e26adf87f37
diff --git a/libhwcomposer/hwc_utils.h b/libhwcomposer/hwc_utils.h
index 7b39ae5..b51fec4 100644
--- a/libhwcomposer/hwc_utils.h
+++ b/libhwcomposer/hwc_utils.h
@@ -170,6 +170,7 @@
 bool needsScaling(hwc_context_t* ctx, hwc_layer_1_t const* layer, const int& dpy);
 bool isAlphaPresent(hwc_layer_1_t const* layer);
 int hwc_vsync_control(hwc_context_t* ctx, int dpy, int enable);
+int getBlending(int blending);
 
 //Helper function to dump logs
 void dumpsys_log(android::String8& buf, const char* fmt, ...);
@@ -275,8 +276,7 @@
 void init_vsync_thread(hwc_context_t* ctx);
 
 inline void getLayerResolution(const hwc_layer_1_t* layer,
-                               int& width, int& height)
-{
+                               int& width, int& height) {
     hwc_rect_t displayFrame  = layer->displayFrame;
     width = displayFrame.right - displayFrame.left;
     height = displayFrame.bottom - displayFrame.top;