imx: Enable RTC (ds1307) support in the U-Boot proper on TPC70 board

The TPC70 is equipped with DS1307 RTC device. Add code to enable support
for it.

Signed-off-by: Lukasz Majewski <lukma@denx.de>
diff --git a/arch/arm/dts/imx6q-kp.dts b/arch/arm/dts/imx6q-kp.dts
index 12d6db6..48ade9e 100644
--- a/arch/arm/dts/imx6q-kp.dts
+++ b/arch/arm/dts/imx6q-kp.dts
@@ -76,6 +76,11 @@
 	pinctrl-names = "default";
 	pinctrl-0 = <&pinctrl_i2c1>;
 	status = "okay";
+
+	ds1307: rtc@32 {
+		compatible = "dallas,ds1307";
+		reg = <0x32>;
+	};
 };
 
 &i2c2 {