mb/google/myst: Enable tis_plat_irq_status

This will fix:
> [INFO ]  Probing TPM I2C: tis_plat_irq_status() not implemented,
wasting 20ms to wait on Cr50!

BUG=b:277297687
TEST=builds

Change-Id: I611a2855d94167748d0f82a478687fe2cdf5846a
Signed-off-by: Jon Murphy <jpmurphy@google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/74286
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>
Reviewed-by: Tim Van Patten <timvp@google.com>
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>

src/mainboard/google/myst/variants/baseboard/Makefile.inc

@@ -1,7 +1,11 @@
 bootblock-y += gpio.c
 
 ramstage-y += gpio.c
+ramstage-y += tpm_tis.c
 
 romstage-y += gpio.c
+romstage-y += tpm_tis.c
+
+verstage-y += tpm_tis.c
 
 smm-y += smihandler.c

src/mainboard/google/myst/variants/baseboard/tpm_tis.c

@@ -0,0 +1,9 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+
+#include <security/tpm/tis.h>
+#include <gpio.h>
+
+int tis_plat_irq_status(void)
+{
+	return gpio_interrupt_status(GPIO_84);
+}