arm64: dts: allwinner: a64: Remove unused address-cells/size-cells of dwmac-sun8i

address-cells/size-cells is unnecessary for dwmac-sun8i node.
It was in early days, but since a mdio node is used, it could be
removed.

This patch fix the following DT warning:
Warning (avoid_unnecessary_addr_size): /soc/ethernet@1c50000: unnecessary #address-cells/#size-cells without "ranges" or child "reg" property
Signed-off-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Maxime Ripard <maxime.ripard@bootlin.com>

arch/arm64/boot/dts/allwinner/sun50i-a64.dtsi

@@ -656,8 +656,6 @@ emac: ethernet@1c30000 {
 			clocks = <&ccu CLK_BUS_EMAC>;
 			clock-names = "stmmaceth";
 			status = "disabled";
-			#address-cells = <1>;
-			#size-cells = <0>;
 
 			mdio: mdio {
 				compatible = "snps,dwmac-mdio";