soc/intel/cannonlake: Add gfx.asl file

Add gfx.asl file for cannonlake SOCs to allow for graphics-related ACPI
devices and methods on cannonlake devices.

BUG=b:142237145
TEST=gfx.asl added to drallion dsdt.asl

Change-Id: I38a26f3135d571e2f9b63840d38fd4d3476fc142
Signed-off-by: Mathew King <mathewk@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/36043
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Simon Glass <sjg@chromium.org>

src/soc/intel/cannonlake/acpi/gfx.asl

@@ -0,0 +1,20 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2019 Google LLC
+ *
+ * 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; version 2 of
+ * the License.
+ *
+ * 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.
+ */
+
+Device (GFX0)
+{
+	Name (_ADR, 0x00020000)
+}

src/soc/intel/cannonlake/acpi/southbridge.asl

@@ -31,6 +31,9 @@
 #include "gpio.asl"
 #endif
 
+/* GFX 00:02.0 */
+#include "gfx.asl"
+
 /* LPC 0:1f.0 */
 #include <soc/intel/common/block/acpi/acpi/lpc.asl>