sdm: Add a property to disable scalar

- Add 'sdm.debug.disable_scalar' property to disable scalar.

Change-Id: Iee0128cc06f1d78ddec011d34086c2c1d7ba3059
diff --git a/sdm/include/utils/debug.h b/sdm/include/utils/debug.h
index 0d64bbf..a384509 100644
--- a/sdm/include/utils/debug.h
+++ b/sdm/include/utils/debug.h
@@ -70,6 +70,7 @@
   static bool IsVideoModeEnabled();
   static bool IsRotatorUbwcDisabled();
   static bool IsRotatorSplitDisabled();
+  static bool IsScalarDisabled();
 
  private:
   Debug();