ARM: dts: nitrogen6x: Add Intersil ISL1208 RTC

This patch adds the battery backed real time clock connected to I2C1
to the device tree.
Signed-off-by: NPhilipp Zabel <p.zabel@pengutronix.de>
Signed-off-by: NShawn Guo <shawn.guo@freescale.com>

arch/arm/boot/dts/imx6qdl-nitrogen6x.dtsi

@@ -192,6 +192,11 @@
 		VDDA-supply = <&reg_2p5v>;
 		VDDIO-supply = <&reg_3p3v>;
 	};
+
+	rtc: rtc@6f {
+		compatible = "isil,isl1208";
+		reg = <0x6f>;
+	};
 };
 
 &i2c2 {