arm64: dts: imx93-var-som: Remove phy-supply from eqos

Per nxp,dwmac-imx.yaml, phy-supply is not a valid property.

Remove it to fix the following dt-schema warning:

imx93-var-som-symphony.dtb: ethernet@428a0000: Unevaluated properties are not allowed ('phy-supply' was unexpected)
	from schema $id: http://devicetree.org/schemas/net/nxp,dwmac-imx.yaml#

The reg_eqos_phy regulator is marked as 'regulator-always-on', so it is
safe to remove the phy-supply property.
Signed-off-by: Fabio Estevam <festevam@denx.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx93-var-som.dtsi

@@ -39,7 +39,6 @@ &eqos {
 	pinctrl-0 = <&pinctrl_eqos>;
 	phy-mode = "rgmii";
 	phy-handle = <&ethphy0>;
-	phy-supply = <&reg_eqos_phy>;
 	status = "okay";
 
 	mdio {