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.cpp b/backend/BackendRCarDu.cpp
index b319d89..0750ee4 100644
--- a/backend/BackendRCarDu.cpp
+++ b/backend/BackendRCarDu.cpp
@@ -22,8 +22,7 @@
 
 namespace android {
 
-bool BackendRCarDu::IsClientLayer(DrmHwcTwo::HwcDisplay *display,
-                                  HwcLayer *layer) {
+bool BackendRCarDu::IsClientLayer(HwcDisplay *display, HwcLayer *layer) {
   hwc_drm_bo_t bo;
 
   int ret = BufferInfoGetter::GetInstance()->ConvertBoInfo(layer->GetBuffer(),