drm_hwcomposer: Rework DrmProperty class

Simplify code and raise-up clang-tidy level of DrmProperty class
to 'normal'.

Signed-off-by: Roman Stratiienko <r.stratiienko@gmail.com>
diff --git a/drm/DrmAtomicStateManager.cpp b/drm/DrmAtomicStateManager.cpp
index 3582b82..16652c1 100644
--- a/drm/DrmAtomicStateManager.cpp
+++ b/drm/DrmAtomicStateManager.cpp
@@ -287,7 +287,7 @@
                                      pipe_->connector->Get()->GetId(),
                                      pipe_->connector->Get()
                                          ->GetDpmsProperty()
-                                         .id(),
+                                         .GetId(),
                                      DRM_MODE_DPMS_ON);
 }