drm_hwcomposer: Convert transform value at HWC hook call

One more step towards "frontend" isolation.

Signed-off-by: Roman Stratiienko <roman.o.stratiienko@globallogic.com>
diff --git a/DrmHwcTwo.h b/DrmHwcTwo.h
index c2da62d..bd45b96 100644
--- a/DrmHwcTwo.h
+++ b/DrmHwcTwo.h
@@ -140,7 +140,7 @@
     int32_t cursor_x_;
     int32_t cursor_y_;
     hwc_color_t layer_color_;
-    HWC2::Transform transform_ = HWC2::Transform::None;
+    DrmHwcTransform transform_ = DrmHwcTransform::kIdentity;
     uint32_t z_order_ = 0;
     DrmHwcBlending blending_ = DrmHwcBlending::kNone;
     DrmHwcColorSpace color_space_ = DrmHwcColorSpace::kUndefined;