ARM: dts: imx7d-nitrogen7: Fix the description of the Wifi clock

According to bindings/regulator/fixed-regulator.txt the 'clocks' and
'clock-names' properties are not valid ones.

In order to turn on the Wifi clock the correct location for describing
the CLKO2 clock is via a mmc-pwrseq handle, so do it accordingly.

Fixes: 56354959cfec ("ARM: dts: imx: add Boundary Devices Nitrogen7 board")
Signed-off-by: Fabio Estevam <festevam@gmail.com>
Acked-by: Troy Kisky <troy.kisky@boundarydevices.com>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm/boot/dts/imx7d-nitrogen7.dts

@@ -86,13 +86,17 @@
 		compatible = "regulator-fixed";
 		regulator-min-microvolt = <3300000>;
 		regulator-max-microvolt = <3300000>;
-		clocks = <&clks IMX7D_CLKO2_ROOT_DIV>;
-		clock-names = "slow";
 		regulator-name = "reg_wlan";
 		startup-delay-us = <70000>;
 		gpio = <&gpio4 21 GPIO_ACTIVE_HIGH>;
 		enable-active-high;
 	};
+
+	usdhc2_pwrseq: usdhc2_pwrseq {
+		compatible = "mmc-pwrseq-simple";
+		clocks = <&clks IMX7D_CLKO2_ROOT_DIV>;
+		clock-names = "ext_clock";
+	};
 };
 
 &adc1 {
@@ -375,6 +379,7 @@
 	bus-width = <4>;
 	non-removable;
 	vmmc-supply = <&reg_wlan>;
+	mmc-pwrseq = <&usdhc2_pwrseq>;
 	cap-power-off-card;
 	keep-power-in-suspend;
 	status = "okay";