mb/lenovo: Add libgfxinit support on Lenovo T520

Change-Id: I4fcdb7467f1911af722f4c24ce64807079a91340
Signed-off-by: Evgeny Zinoviev <me@ch1p.com>
Reviewed-on: https://review.coreboot.org/28620
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Martin Roth <martinroth@google.com>

src/mainboard/lenovo/t520/Kconfig

@@ -15,6 +15,7 @@ config BOARD_LENOVO_BASEBOARD_T520
 	select HAVE_ACPI_RESUME
 	select INTEL_INT15
 	select SANDYBRIDGE_IVYBRIDGE_LVDS
+	select MAINBOARD_HAS_LIBGFXINIT
 	select MAINBOARD_HAS_LPC_TPM
 	select MAINBOARD_HAS_TPM1
 	select DRIVERS_LENOVO_HYBRID_GRAPHICS

src/mainboard/lenovo/t520/Makefile.inc

@@ -16,3 +16,4 @@
 smm-$(CONFIG_HAVE_SMI_HANDLER) += smihandler.c
 romstage-y += variants/$(VARIANT_DIR)/gpio.c
 romstage-y += variants/$(VARIANT_DIR)/romstage.c
+ramstage-$(CONFIG_MAINBOARD_USE_LIBGFXINIT) += gma-mainboard.ads

src/mainboard/lenovo/t520/gma-mainboard.ads

@@ -0,0 +1,34 @@
+--
+-- This file is part of the coreboot project.
+--
+-- 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;
+with HW.GFX.GMA.Display_Probing;
+
+use HW.GFX.GMA;
+use HW.GFX.GMA.Display_Probing;
+
+private package GMA.Mainboard is
+
+   ports : constant Port_List :=
+     (DP1,
+      DP2,
+      DP3,
+      HDMI1,
+      HDMI2,
+      HDMI3,
+      Analog,
+      Internal,
+      others => Disabled);
+
+end GMA.Mainboard;