drm_hwcomposer: Initialize HwcDisplay using DrmDisplayPIpeline

HwcDisplay can now take all necessary objects from DrmDisplayPipeline.

Signed-off-by: Roman Stratiienko <roman.o.stratiienko@globallogic.com>
diff --git a/drm/ResourceManager.h b/drm/ResourceManager.h
index f54d682..caeb098 100644
--- a/drm/ResourceManager.h
+++ b/drm/ResourceManager.h
@@ -33,8 +33,8 @@
   ~ResourceManager();
 
   int Init();
-  DrmDevice *GetDrmDevice(int display);
-  const std::vector<std::unique_ptr<DrmDevice>> &GetDrmDevices() const {
+  auto GetPipeline(int display) -> DrmDisplayPipeline *;
+  auto &GetDrmDevices() const {
     return drms_;
   }
   int GetDisplayCount() const {