mainboard/google/corsola: Fix incorrect timestamps in the eventlog

Timestamp '2000-00-00 00:00:00' is considered as the invalid format.
Enable RTC to fix incorrect timestamp format in the eventlog.

BUG=b:232035991
TEST=check the timestamp field in /var/log/eventlog.txt

Change-Id: I8d9822075377734ef4a609ddeee79385fe7af0f0
Signed-off-by: Yidi Lin <yidilin@chromium.org>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/64585
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
Reviewed-by: Yu-Ping Wu <yupingso@google.com>
Reviewed-by: Rex-BC Chen <rex-bc.chen@mediatek.com>

src/mainboard/google/corsola/Kconfig

@@ -40,6 +40,7 @@ config BOARD_SPECIFIC_OPTIONS
 	select HAVE_LINEAR_FRAMEBUFFER
 	select DRIVER_ANALOGIX_ANX7625
 	select DRIVER_PARADE_PS8640
+	select RTC
 
 config MAINBOARD_DIR
 	string