drm_hwcomposer: Stop using HWC2 hooks for layer transform

Add a transform member to LayerProperties.

Change-Id: Id81386ce1565941e477534717cefb745de8738ca
Signed-off-by: Drew Davenport <ddavenport@google.com>
diff --git a/hwc2_device/HwcLayer.h b/hwc2_device/HwcLayer.h
index 31bafed..ed84219 100644
--- a/hwc2_device/HwcLayer.h
+++ b/hwc2_device/HwcLayer.h
@@ -37,6 +37,7 @@
     std::optional<hwc_rect_t> display_frame;
     std::optional<float> alpha;
     std::optional<hwc_frect_t> source_crop;
+    std::optional<LayerTransform> transform;
   };
 
   explicit HwcLayer(HwcDisplay *parent_display) : parent_(parent_display){};