arm64: dts: imx8mq-librem5: Use 'vqmmc-supply'

'power-supply' is an invalid property for usdhc and it gives
the following schema warning:

imx8mq-librem5-r2.dtb: mmc@30b40000: Unevaluated properties are not allowed ('power-supply' was unexpected)
From schema: Documentation/devicetree/bindings/mmc/fsl-imx-esdhc.yaml

Change it to 'vqmmc-supply', which represents the supply for the bus IO.
Signed-off-by: Fabio Estevam <festevam@denx.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mq-librem5.dtsi

@@ -1376,7 +1376,7 @@ &usdhc1 {
 	pinctrl-2 = <&pinctrl_usdhc1_200mhz>;
 	bus-width = <8>;
 	vmmc-supply = <&reg_vdd_3v3>;
-	power-supply = <&reg_vdd_1v8>;
+	vqmmc-supply = <&reg_vdd_1v8>;
 	non-removable;
 	status = "okay";
 };