imx31: add rtc device on litekit board.
This patch adds support for SoC build-in RTC device on litekit board.
Signed-off-by: Vladimir Zapolskiy <vzapolskiy@gmail.com>
Cc: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>