gma broxton: Add final glue

Add new configuration flags for Broxton and hook up its DDI_Phy
implementation in the shared Haswell DDI code. Haswell and Skylake
get DDI_Phy stubs.

Tested (in Linux userspace) on ASRock J3455-ITX which exposes the
following ports:
  o VGA through an active eDP to VGA converter chip
  o HDMI 2.0 through an active DP to HDMI converter chip
  o DVI-D connected to the SoC

Change-Id: If72b228c6a4c45487261e6e7435d281ec2d97f38
Signed-off-by: Nico Huber <nico.huber@secunet.com>
Reviewed-on: https://review.coreboot.org/18426
Tested-by: Nico Huber <nico.h@gmx.de>
Reviewed-by: Arthur Heymans <arthur@aheymans.xyz>
diff --git a/common/haswell_shared/hw-gfx-gma-ddi_phy_stub.ads b/common/haswell_shared/hw-gfx-gma-ddi_phy_stub.ads
new file mode 100644
index 0000000..b37e955
--- /dev/null
+++ b/common/haswell_shared/hw-gfx-gma-ddi_phy_stub.ads
@@ -0,0 +1,35 @@
+--
+-- Copyright (C) 2017 secunet Security Networks AG
+--
+-- This program is free software; you can redistribute it and/or modify
+-- it under the terms of the GNU General Public License as published by
+-- the Free Software Foundation; either version 2 of the License, or
+-- (at your option) any later version.
+--
+-- This program is distributed in the hope that it will be useful,
+-- but WITHOUT ANY WARRANTY; without even the implied warranty of
+-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+-- GNU General Public License for more details.
+--
+
+with HW.GFX.GMA.DP_Info;
+
+private package HW.GFX.GMA.DDI_Phy_Stub is
+
+   subtype DDI_Phy_Port is GPU_Port;
+
+   Max_V_Swing : constant DP_Info.DP_Voltage_Swing := DP_Info.VS_Level_0;
+
+   type Emph_Array is array (DP_Info.DP_Voltage_Swing) of DP_Info.DP_Pre_Emph;
+   Max_Pre_Emph : constant Emph_Array := (others => DP_Info.Emph_Level_0);
+
+   procedure Set_DP_Signal_Levels
+     (Port        : Digital_Port;
+      Train_Set   : DP_Info.Train_Set) is null;
+
+   type HDMI_Buf_Trans_Range is range 0 .. 9;
+   procedure Set_HDMI_Signal_Levels
+     (Port  : DDI_Phy_Port;
+      Level : HDMI_Buf_Trans_Range) is null;
+
+end HW.GFX.GMA.DDI_Phy_Stub;