ARM: dts: add 'rtc_src' clock to rtc node for exynos5422-odroidxu3

The Exynos5422 SoC has a s3c6410 RTC where the source clock
is now a mandatory property.

This patch fixes probe failure of s3c-rtc on Odroid-XU3 boards.
Signed-off-by: Markus Reichl <m.reichl@fivetechno.de>
Tested-by: Anand Moon <linux.amoon@gmail.com>
Reviewed-by: Chanwoo Choi <cw00.choi@samsung.com>
Reviewed-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
Signed-off-by: Krzysztof Kozlowski <k.kozlowski.k@gmail.com>
Signed-off-by: Kukjin Kim <kgene@kernel.org>

arch/arm/boot/dts/exynos5422-odroidxu3.dts

@@ -11,6 +11,7 @@
 */
 
 /dts-v1/;
+#include <dt-bindings/clock/samsung,s2mps11.h>
 #include <dt-bindings/gpio/gpio.h>
 #include "exynos5800.dtsi"
 
@@ -283,10 +284,6 @@ hdmiddc@50 {
 		};
 	};
 
-	rtc@101E0000 {
-		status = "okay";
-	};
-
 	leds {
 		compatible = "gpio-leds";
 		heartbeat {
@@ -415,3 +412,9 @@ ina231@45 {
 		shunt-resistor = <10000>;
 	};
 };
+
+&rtc {
+	status = "okay";
+	clocks = <&clock CLK_RTC>, <&s2mps11_osc S2MPS11_CLK_AP>;
+	clock-names = "rtc", "rtc_src";
+};