mb/google/brya/var/mithrax: Add WiFi SAR table for mithrax

Add WiFi SAR table for mithrax.

BUG=b:231491014
TEST=emerge-brya chromeos-config chromeos-config-bsp-private
coreboot-private-files-baseboard-brya coreboot chromeos-bootimage
and checked SAR table can load by WiFi driver.

Signed-off-by: John Su <john_su@compal.corp-partner.google.com>
Change-Id: I847debd7c817225b5b1777c798a14ef10aee3471
Reviewed-on: https://review.coreboot.org/c/coreboot/+/64541
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Subrata Banik <subratabanik@google.com>
Reviewed-by: Frank Wu <frank_wu@compal.corp-partner.google.com>

src/mainboard/google/brya/Kconfig.name

@@ -219,6 +219,7 @@ config BOARD_GOOGLE_OSIRIS
 config BOARD_GOOGLE_MITHRAX
 	bool "->  Mithrax"
 	select BOARD_GOOGLE_BASEBOARD_BRYA
+	select CHROMEOS_WIFI_SAR if CHROMEOS
 	select DRIVERS_GENERIC_GPIO_KEYS
 	select DRIVERS_GENESYSLOGIC_GL9755
 

src/mainboard/google/brya/variants/mithrax/Makefile.inc

@@ -1,3 +1,5 @@
 # SPDX-License-Identifier: GPL-2.0-only
 bootblock-y += gpio.c
 ramstage-y += gpio.c
+
+ramstage-$(CONFIG_FW_CONFIG) += variant.c

src/mainboard/google/brya/variants/mithrax/variant.c

@@ -3,6 +3,12 @@
 #include <chip.h>
 #include <fw_config.h>
 #include <baseboard/variants.h>
+#include <sar.h>
+
+const char *get_wifi_sar_cbfs_filename(void)
+{
+	return "wifi_sar_0.hex";
+}
 
 void variant_update_soc_chip_config(struct soc_intel_alderlake_config *config)
 {