chromeos chipsets: select RTC usage

Since RTC is now a Kconfig ensure RTC is selected on the
x86 chipsets which are in Chrome OS devices. This allows
the eventlog to have proper timestamps instead of all
zeros.

BUG=chrome-os-partner:55993

Change-Id: I24ae7d9b3bf43a5791d4dc04aae018ce17fda72b
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://review.coreboot.org/16086
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Tested-by: build bot (Jenkins)
Reviewed-by: Furquan Shaikh <furquan@google.com>
diff --git a/src/soc/intel/skylake/Kconfig b/src/soc/intel/skylake/Kconfig
index 0ecc80d..b08c004 100644
--- a/src/soc/intel/skylake/Kconfig
+++ b/src/soc/intel/skylake/Kconfig
@@ -37,6 +37,7 @@
 	select REG_SCRIPT
 	select RELOCATABLE_MODULES
 	select RELOCATABLE_RAMSTAGE
+	select RTC
 	select SOC_INTEL_COMMON
 	select SOC_INTEL_COMMON_ACPI_WAKE_SOURCE
 	select SOC_INTEL_COMMON_LPSS_I2C