mb/google/skyrim: Select GOOGLE_SMBIOS_MAINBOARD_VERSION

Select GOOGLE_SMBIOS_MAINBOARD_VERSION allows querying
board revision from the EC.

BUG=b:256723358
TEST=1. emerge-skyrim coreboot chromeos-bootimage
     2. flash the image to the device and check board rev
        by using command `dmidecode -t 1 | grep Version`

Change-Id: I97295083dbca1c285ef7359d86abac7315c654c9
Signed-off-by: Amanda Huang <amanda_hwang@compal.corp-partner.google.com>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/69087
Reviewed-by: Frank Wu <frank_wu@compal.corp-partner.google.com>
Reviewed-by: Karthik Ramasubramanian <kramasub@google.com>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Ian Feng <ian_feng@compal.corp-partner.google.com>
Reviewed-by: Jon Murphy <jpmurphy@google.com>
Reviewed-by: Eric Lai <eric_lai@quanta.corp-partner.google.com>

src/mainboard/google/skyrim/Kconfig

@@ -32,6 +32,7 @@ config BOARD_SPECIFIC_OPTIONS
 	select ELOG_GSMI
 	select FW_CONFIG
 	select FW_CONFIG_SOURCE_CHROMEEC_CBI
+	select GOOGLE_SMBIOS_MAINBOARD_VERSION
 	select I2C_TPM
 	select MAINBOARD_HAS_CHROMEOS
 	select MAINBOARD_HAS_TPM2