arm: dts: add ethernet related node for MT7629 SoC

This patch adds ethernet gmac node for MT7629 with internal gigabit phy.

Signed-off-by: Mark Lee <Mark-MC.Lee@mediatek.com>
diff --git a/arch/arm/dts/mt7629-rfb.dts b/arch/arm/dts/mt7629-rfb.dts
index a6d28a0..95d10aa 100644
--- a/arch/arm/dts/mt7629-rfb.dts
+++ b/arch/arm/dts/mt7629-rfb.dts
@@ -22,6 +22,17 @@
 	};
 };
 
+&eth {
+	status = "okay";
+	mediatek,gmac-id = <1>;
+	phy-mode = "gmii";
+	phy-handle = <&phy0>;
+
+	phy0: ethernet-phy@0 {
+		reg = <0>;
+	};
+};
+
 &pinctrl {
 	qspi_pins: qspi-pins {
 		mux {