Now that RTC support has been enabled for i.MX35, add RTC to the mx35_3ds board.

Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: <linux-arm-kernel@lists.infradead.org>
Signed-off-by: NBenoît Thébaudeau <benoit.thebaudeau@advansee.com>
Signed-off-by: NSascha Hauer <s.hauer@pengutronix.de>