drm_hwcomposer: Move HwcDisplay out of DrmHwcTwo class

Reduces code complexity.

Closes: https://gitlab.freedesktop.org/drm-hwcomposer/drm-hwcomposer/-/issues/35
Signed-off-by: Roman Stratiienko <roman.o.stratiienko@globallogic.com>
diff --git a/backend/BackendRCarDu.h b/backend/BackendRCarDu.h
index 862bef2..1259c9f 100644
--- a/backend/BackendRCarDu.h
+++ b/backend/BackendRCarDu.h
@@ -23,7 +23,7 @@
 
 class BackendRCarDu : public Backend {
  public:
-  bool IsClientLayer(DrmHwcTwo::HwcDisplay *display, HwcLayer *layer) override;
+  bool IsClientLayer(HwcDisplay *display, HwcLayer *layer) override;
 };
 }  // namespace android