ARM: dts: imx6ul-14x14-evk: Remove unnecessary node

imx6ul.dtsi already contains:

cpu0: cpu@0 {
	....
	arm-supply = <&reg_arm>;
	soc-supply = <&reg_soc>;
};

, so remove the duplication.

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