ARM: dts: imx6sx-nitrogen6sx: drop incorrect regulator clock-names

regulator-fixed does not take "clock-names" property:

  imx6sx-nitrogen6sx.dtb: regulator-wlan: Unevaluated properties are not allowed ('clock-names' was unexpected)
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/nxp/imx/imx6sx-nitrogen6sx.dts

@@ -72,7 +72,6 @@ reg_wlan: regulator-wlan {
 		pinctrl-0 = <&pinctrl_reg_wlan>;
 		compatible = "regulator-fixed";
 		clocks = <&clks IMX6SX_CLK_CKO>;
-		clock-names = "slow";
 		regulator-name = "wlan-en";
 		regulator-min-microvolt = <3300000>;
 		regulator-max-microvolt = <3300000>;