ARM64: dts: meson-gxbb-p200: add the ethernet PHY's reset GPIO

This resets the ethernet PHY during boot to get the PHY into a "clean"
state.
While here also specify the phy-handle of the ethmac node to make the
PHY configuration similar to the one we have on GXL devices. This will
allow us to specify OF-properties for the PHY itself.
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Tested-by: Neil Armstrong <narmstrong@baylibre.com>
Reviewed-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>

arch/arm64/boot/dts/amlogic/meson-gxbb-p200.dts

@@ -96,6 +96,29 @@ button-menu {
 	};
 };
 
+&ethmac {
+	status = "okay";
+	pinctrl-0 = <&eth_rgmii_pins>;
+	pinctrl-names = "default";
+	phy-handle = <&eth_phy0>;
+	phy-mode = "rgmii";
+
+	snps,reset-gpio = <&gpio GPIOZ_14 0>;
+	snps,reset-delays-us = <0 10000 1000000>;
+	snps,reset-active-low;
+
+	mdio {
+		compatible = "snps,dwmac-mdio";
+		#address-cells = <1>;
+		#size-cells = <0>;
+
+		eth_phy0: ethernet-phy@3 {
+			/* Micrel KSZ9031 (0x00221620) */
+			reg = <3>;
+		};
+	};
+};
+
 &i2c_B {
 	status = "okay";
 	pinctrl-0 = <&i2c_b_pins>;