feat: enable Portenta H7 ethernet

Author: razvanphp

variants/arduino_portenta_h7_stm32h747xx_m7/arduino_portenta_h7_stm32h747xx_m7.overlay

@@ -122,6 +122,30 @@
 	status = "okay";
 };
 
+&mac {
+	pinctrl-0 = < &eth_ref_clk_pa1
+		      &eth_crs_dv_pa7
+		      &eth_rxd0_pc4
+		      &eth_rxd1_pc5
+		      &eth_tx_en_pg11
+		      &eth_txd1_pg12
+		      &eth_txd0_pg13 >;
+	pinctrl-names = "default";
+	status = "okay";
+};
+
+&mdio {
+	status = "okay";
+	pinctrl-0 = <&eth_mdio_pa2 &eth_mdc_pc1>;
+	pinctrl-names = "default";
+
+	ethernet-phy@0 {
+		compatible = "ethernet-phy";
+		reg = <0x00>;
+		status = "okay";
+	};
+};
+
 &dmamux1 {
 	status = "okay";
 };