boards: sam_e70_xplained: add support for PHY driver

Update to dts file to use the generic MII PHY driver.

Signed-off-by: Arvin Farahmand <[email protected]>

Author: arvinf

boards/arm/sam_e70_xplained/sam_e70_xplained-common.dtsi

@@ -89,6 +89,17 @@ zephyr_udc0: &usbhs {
 
 &gmac {
 	status = "okay";
+
+	phy: phy {
+		compatible = "ethernet-phy";
+		status = "okay";
+		address = <0>;
+		mdio = <&mdio>;
+	};
+};
+
+&mdio {
+	status = "okay";
 };
 
 &pwm0 {