mb/starlabs/starbook/mtl: Make TCSS notify the IGD of changes

Set the UPD `TcNotifyIgd` to `2` (Auto), so that the TCSS subsystem
will notify the Integrated Graphics of display changes.

Change-Id: I2b47a534f0816545fe58bde8963c56f0455871eb
Signed-off-by: Sean Rhodes <sean@starlabs.systems>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/89054
Reviewed-by: Matt DeVillier <matt.devillier@gmail.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/starlabs/starbook/variants/mtl/Makefile.mk

@@ -7,5 +7,6 @@ romstage-y += romstage.c
 ramstage-y += devtree.c
 ramstage-y += gpio.c
 ramstage-y += hda_verb.c
+ramstage-y += ramstage.c
 
 $(call add_vbt_to_cbfs, vbt_native_res.bin, data_native_res.vbt)

src/mainboard/starlabs/starbook/variants/mtl/ramstage.c

@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+
+#include <option.h>
+#include <soc/ramstage.h>
+
+void mainboard_silicon_init_params(FSP_S_CONFIG *supd)
+{
+	supd->TcNotifyIgd = 2; // Auto
+}