arm64: dts: mediatek: mt7986: drop invalid properties from ethsys

Mediatek ethsys controller / syscon binding doesn't allow any subnodes
so "#address-cells" and "#size-cells" are redundant (actually:
disallowed).

This fixes:
arch/arm64/boot/dts/mediatek/mt7986a-bananapi-bpi-r3.dtb: syscon@15000000: '#address-cells', '#size-cells' do not match any of the regexes: 'pinctrl-[0-9]+'
        from schema $id: http://devicetree.org/schemas/clock/mediatek,ethsys.yaml#

Fixes: 1f9986b2 ("arm64: dts: mediatek: add clock support for mt7986a")
Cc: Sam Shih <sam.shih@mediatek.com>
Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
Link: https://lore.kernel.org/r/20240213053739.14387-1-zajec5@gmail.comSigned-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>

arch/arm64/boot/dts/mediatek/mt7986a.dtsi

@@ -492,8 +492,6 @@ ethsys: syscon@15000000 {
 			 compatible = "mediatek,mt7986-ethsys",
 				      "syscon";
 			 reg = <0 0x15000000 0 0x1000>;
-			 #address-cells = <1>;
-			 #size-cells = <1>;
 			 #clock-cells = <1>;
 			 #reset-cells = <1>;
 		};