drivers/intel/gma: License libgfxinit glue code under GPL v2

Change-Id: I7a78e16512369cbaada4399dbb855ade358ff046
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/41521
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Angel Pons <th3fanbus@gmail.com>
Reviewed-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-by: Jacob Garber <jgarber1@ualberta.ca>

src/drivers/intel/gma/gma-gfx_init.ads

@@ -1,3 +1,5 @@
+-- SPDX-License-Identifier: GPL-2.0-only
+
 with Interfaces.C;
 
 with HW;

src/drivers/intel/gma/gma.adb

@@ -1,3 +1,5 @@
+-- SPDX-License-Identifier: GPL-2.0-only
+
 with HW.GFX.GMA;
 with HW.GFX.GMA.Display_Probing;
 

src/drivers/intel/gma/gma.ads

@@ -1,3 +1,5 @@
+-- SPDX-License-Identifier: GPL-2.0-only
+
 with Interfaces.C;
 
 with HW.GFX.EDID;

src/drivers/intel/gma/hires_fb/gma-gfx_init.adb

@@ -1,3 +1,5 @@
+-- SPDX-License-Identifier: GPL-2.0-only
+
 with CB.Config;
 
 use CB;

src/drivers/intel/gma/text_fb/gma-gfx_init.adb

@@ -1,3 +1,5 @@
+-- SPDX-License-Identifier: GPL-2.0-only
+
 with HW.GFX;
 with HW.GFX.GMA;
 with HW.GFX.GMA.Display_Probing;