ARM: dts: imx7-colibri: specify cpu-supply

Specify CPU supply using the "cpu-supply" property instead of
the invalid "arm-supply" property.

Signed-off-by: Stefan Agner <[e-mail]>
Reviewed-by: Fabio Estevam <[e-mail]>
Signed-off-by: Shawn Guo <[e-mail]>

arch/arm/boot/dts/imx7-colibri.dtsi

···
 };
 
 &cpu0 {
-	arm-supply = <&reg_DCDC2>;
+	cpu-supply = <&reg_DCDC2>;
 };
 
 &fec1 {