drivers/rtc/rtc-lpc32xx.c: add device tree support

Adds device tree support for rtc-lpc32xx.c

Signed-off-by: Roland Stigge <stigge@antcom.de>
Acked-by: Rob Herring <rob.herring@calxeda.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/devicetree/bindings/rtc/lpc32xx-rtc.txt

@@ -0,0 +1,15 @@
+* NXP LPC32xx SoC Real Time Clock controller
+
+Required properties:
+- compatible: must be "nxp,lpc3220-rtc"
+- reg: physical base address of the controller and length of memory mapped
+  region.
+- interrupts: The RTC interrupt
+
+Example:
+
+	rtc@40024000 {
+		compatible = "nxp,lpc3220-rtc";
+		reg = <0x40024000 0x1000>;
+		interrupts = <52 0>;
+	};