gma bxt panel: Correct panel backlight handling

Change-Id: Icfad261fb4d5ff478974948c0148880c5b8cb40c
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/c/libgfxinit/+/38265
Tested-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
diff --git a/common/hw-gfx-gma-panel.ads b/common/hw-gfx-gma-panel.ads
index baf47f7..2a97f0e 100644
--- a/common/hw-gfx-gma-panel.ads
+++ b/common/hw-gfx-gma-panel.ads
@@ -54,8 +54,8 @@
 
    procedure Backlight_Off (Panel : Panel_Control);
 
-   procedure Set_Backlight (Panel : Panel_Control; Level : Word16);
+   procedure Set_Backlight (Panel : Panel_Control; Level : Word32);
 
-   procedure Get_Max_Backlight (Panel : Panel_Control; Level : out Word16);
+   procedure Get_Max_Backlight (Panel : Panel_Control; Level : out Word32);
 
 end HW.GFX.GMA.Panel;