ARM: imx: imx8mn-*-evk: use DM settings for PHY configuration

With the correct settings described in the device-tree the PHY settings
in the board init are no longer required. The values are taken from the
linux device tree.

The PHY latency settings are derived from the phy-mode property and the
voltage seetings are done via the regulator.

Suggested-by: Michael Walle <michael@walle.cc>
Signed-off-by: Heiko Thiery <heiko.thiery@gmail.com>
Tested-by: Marek Vasut <marex@denx.de> # 8MNANOD4-EVK
Reviewed-by: Fabio Estevam <festevam@gmail.com>
diff --git a/arch/arm/dts/imx8mn-evk.dtsi b/arch/arm/dts/imx8mn-evk.dtsi
index 416fadb..fc2c7f1 100644
--- a/arch/arm/dts/imx8mn-evk.dtsi
+++ b/arch/arm/dts/imx8mn-evk.dtsi
@@ -64,6 +64,12 @@
 		ethphy0: ethernet-phy@0 {
 			compatible = "ethernet-phy-ieee802.3-c22";
 			reg = <0>;
+			vddio-supply = <&vddio>;
+
+			vddio: vddio-regulator {
+				regulator-min-microvolt = <1800000>;
+				regulator-max-microvolt = <1800000>;
+			};
 		};
 	};
 };