arm: dts: mt7623: Update ethsys binding

The ethsys binding misses the reset-cells, this patch
adds this property.
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Matthias Brugger <matthias.bgg@gmail.com>

arch/arm/boot/dts/mt7623.dtsi

@@ -758,6 +758,7 @@ ethsys: syscon@1b000000 {
 			     "syscon";
 		reg = <0 0x1b000000 0 0x1000>;
 		#clock-cells = <1>;
+		#reset-cells = <1>;
 	};
 
 	eth: ethernet@1b100000 {