ARM: dts: imx6ul: add clock-frequency to CPU node

Add clock-frequency property to CPU node. Avoids warnings like
"/cpus/cpu@0 missing clock-frequency property" for "arm,cortex-a7".
Signed-off-by: Anson Huang <Anson.Huang@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx6ul.dtsi

@@ -59,6 +59,7 @@ cpu0: cpu@0 {
 			compatible = "arm,cortex-a7";
 			device_type = "cpu";
 			reg = <0>;
+			clock-frequency = <696000000>;
 			clock-latency = <61036>; /* two CLK32 periods */
 			#cooling-cells = <2>;
 			operating-points = <

arch/arm/boot/dts/imx6ull.dtsi

@@ -12,6 +12,7 @@
 /delete-node/ &crypto;
 
 &cpu0 {
+	clock-frequency = <900000000>;
 	operating-points = <
 		/* kHz	uV */
 		900000	1275000