gma config: Introduce Have_HDMI_Buf_Override

Change-Id: Id00ae200cc8d08ce245d57b2886a40f0fea10167
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/libgfxinit/+/27049
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
diff --git a/common/haswell_shared/hw-gfx-gma-connectors-ddi.adb b/common/haswell_shared/hw-gfx-gma-connectors-ddi.adb
index 88f2b22..7f179ff 100644
--- a/common/haswell_shared/hw-gfx-gma-connectors-ddi.adb
+++ b/common/haswell_shared/hw-gfx-gma-connectors-ddi.adb
@@ -679,8 +679,7 @@
          then
             declare
                HDMI_Level : constant DDI_Phy.HDMI_Buf_Trans_Range :=
-                 (if Config.DDI_HDMI_Buffer_Translation
-                     in DDI_Phy.HDMI_Buf_Trans_Range
+                 (if Config.Have_HDMI_Buf_Override
                   then Config.DDI_HDMI_Buffer_Translation
                   else Config.Default_DDI_HDMI_Buffer_Translation);
             begin