ARM: dts: imx: Adjust CPU nodes

Make CPU nodes consistent throughout the i.MX dts files, which
also matches the description from ePAPR spec.

This also fixes the following W=1 warning in some cases:

Warning (unit_address_vs_reg): Node /cpus/cpu@0 has a unit name, but no reg property

Signed-off-by: Fabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx25.dtsi

@@ -43,12 +43,13 @@
 	};
 
 	cpus {
-		#address-cells = <0>;
+		#address-cells = <1>;
 		#size-cells = <0>;
 
-		cpu {
+		cpu@0 {
 			compatible = "arm,arm926ej-s";
 			device_type = "cpu";
+			reg = <0>;
 		};
 	};