arm64: dts: meson: sei510: add network support

Enable the network interface of the SEI510 which use the internal PHY.
Tested-by: Kevin Hilman <khilman@baylibre.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Kevin Hilman <khilman@baylibre.com>

arch/arm64/boot/dts/amlogic/meson-g12a-sei510.dts

@@ -29,6 +29,7 @@ button-onoff {
 
 	aliases {
 		serial0 = &uart_AO;
+		ethernet0 = &ethmac;
 	};
 
 	chosen {
@@ -149,6 +150,12 @@ cvbs_vdac_out: endpoint {
 	};
 };
 
+&ethmac {
+	status = "okay";
+	phy-handle = <&internal_ephy>;
+	phy-mode = "rmii";
+};
+
 &hdmi_tx {
 	status = "okay";
 	pinctrl-0 = <&hdmitx_hpd_pins>, <&hdmitx_ddc_pins>;