arm64: dts: imx8mp: Adjust EQoS PHY address on i.MX8MP DHCOM

The current variant of the SoM has LAN8740Ai PHY connected to EQoS
strapped to MDIO address 0 , adjust the MDIO address to match the
hardware.
Signed-off-by: Marek Vasut <marex@denx.de>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>

arch/arm64/boot/dts/freescale/imx8mp-dhcom-som.dtsi

@@ -94,14 +94,14 @@ mdio {
 		#size-cells = <0>;
 
 		/* Up to one of these two PHYs may be populated. */
-		ethphy0f: ethernet-phy@1 { /* SMSC LAN8740Ai */
+		ethphy0f: ethernet-phy@0 { /* SMSC LAN8740Ai */
 			compatible = "ethernet-phy-id0007.c110",
 				     "ethernet-phy-ieee802.3-c22";
 			interrupt-parent = <&gpio3>;
 			interrupts = <19 IRQ_TYPE_LEVEL_LOW>;
 			pinctrl-0 = <&pinctrl_ethphy0>;
 			pinctrl-names = "default";
-			reg = <1>;
+			reg = <0>;
 			reset-assert-us = <1000>;
 			reset-deassert-us = <1000>;
 			reset-gpios = <&gpio3 20 GPIO_ACTIVE_LOW>;