ramips: rt3883: fix dtc compiler warning

Fixes the following compiler warning:

Warning (reg_format): "reg" property in /ethernet@10100000/port@0 has invalid length (4 bytes) (#address-cells == 2, #size-cells == 1)
Warning (avoid_default_addr_size): Relying on default #address-cells value for /ethernet@10100000/port@0
Warning (avoid_default_addr_size): Relying on default #size-cells value for /ethernet@10100000/port@0

Signed-off-by: Mathias Kresin <dev@kresin.me>

target/linux/ramips/dts/rt3883.dtsi

@@ -306,6 +306,8 @@
 
 	ethernet: ethernet@10100000 {
 		compatible = "ralink,rt3883-eth";
+		#address-cells = <1>;
+		#size-cells = <0>;
 		reg = <0x10100000 0x10000>;
 
 		resets = <&rstctrl 21>;