gma skl: Add DDI buffer translations

Change-Id: Ibb058de78f671b94ee788f30342184a8c31a1154
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/20167
Tested-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Stefan Reinauer <stefan.reinauer@coreboot.org>
diff --git a/common/hw-gfx-gma-config.ads.template b/common/hw-gfx-gma-config.ads.template
index 6839b91..ec41c40 100644
--- a/common/hw-gfx-gma-config.ads.template
+++ b/common/hw-gfx-gma-config.ads.template
@@ -92,7 +92,8 @@
                                                   and CPU_Var = Normal)
                                                  or CPU >= Skylake;
 
-   Has_DDI_Buffer_Trans    : constant Boolean := CPU in Haswell .. Broadwell;
+   Has_DDI_Buffer_Trans    : constant Boolean := CPU >= Haswell and
+                                                 CPU /= Broxton;
    Has_Low_Voltage_Swing   : constant Boolean := CPU >= Broxton;
 
    Need_DP_Aux_Mutex       : constant Boolean := False; -- Skylake & (PSR | GTC)
@@ -214,6 +215,7 @@
          when Haswell   => 6,
          when Broadwell => 7,
          when Broxton   => 8,
+         when Skylake   => 8,
          when others    => 0);
 
    ----------------------------------------------------------------------------