drivers/rtc/rtc-imxdi.c: add devicetree support

Add device tree support to the rtc-imxdi driver.

Signed-off-by: Roland Stigge <stigge@antcom.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: Sascha Hauer <kernel@pengutronix.de>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>