sde: partial update implementation

  1. Partial update for non-split and split panels.
  2. Currently, partial update is enabled on qualified
     primary displays only.
Change-Id: I4d37e83e0991693cce950dc1428ed8c30d4f6caa
diff --git a/displayengine/include/utils/debug.h b/displayengine/include/utils/debug.h
index 2cef5d7..1dbf0c3 100644
--- a/displayengine/include/utils/debug.h
+++ b/displayengine/include/utils/debug.h
@@ -65,7 +65,7 @@
   static uint32_t GetIdleTimeoutMs();
   static bool IsRotatorDownScaleDisabled();
   static bool IsDecimationDisabled();
-  static bool IsPartialUpdate();
+  static bool IsPartialUpdateEnabled();
 
  private:
   Debug();