display: Add API to set luminance

-Add API to set min/max luminance range for given display.
-using API via binder
 adb shell "vndservice call display.qservice 46 i32 <display_id>
 f <min_lum> f <max_lum>"

Change-Id: I97c31b18cac4ab8ac45518833d0964b7e54c9d58
diff --git a/libqdutils/display_config.h b/libqdutils/display_config.h
index c0952b0..ad41ed7 100644
--- a/libqdutils/display_config.h
+++ b/libqdutils/display_config.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2013 - 2016, 2018, The Linux Foundation. All rights reserved.
+ * Copyright (c) 2013 - 2016, 2018, 2019, The Linux Foundation. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
@@ -171,6 +171,9 @@
 // Get supported bit clk values.
 int getSupportedBitClk(int dpy, std::vector<uint64_t>& bit_rates);
 
+// Sets the specified min and max luminance values.
+int setPanelLuminanceAttributes(int dpy, float min_lum, float max_lum);
+
 }; //namespace