ARM: dts: Add missing frequency property to exynos5250

Added missing clock frequency property to CPU node to avoid
boot time warnings.
Signed-off-by: Sachin Kamat <sachin.kamat@linaro.org>
Reviewed-by: Tomasz Figa <t.figa@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>

arch/arm/boot/dts/exynos5250.dtsi

@@ -60,11 +60,13 @@ cpu@0 {
 			device_type = "cpu";
 			compatible = "arm,cortex-a15";
 			reg = <0>;
+			clock-frequency = <1700000000>;
 		};
 		cpu@1 {
 			device_type = "cpu";
 			compatible = "arm,cortex-a15";
 			reg = <1>;
+			clock-frequency = <1700000000>;
 		};
 	};