realtek: dts: fix Zyxel GS1920 port section

For the GS1920 the build system throws errors like

../dts/rtl8392_zyxel_gs1920-24hp-v1.dts:256.19-29:
Warning (reg_format): /switch@1b000000/ports/port@0:reg:
property has invalid length (4 bytes)
(#address-cells == 2, #size-cells == 1)

The dts misses the address and size properties for the
ports section. Fix that.

Fixes: 2a55846 ("realtek: add support for ZyXEL GS1920-24HPv1")
Signed-off-by: Markus Stockhausen <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/21534
Signed-off-by: Robert Marko <[email protected]>

target/linux/realtek/dts/rtl8392_zyxel_gs1920-24hp-v1.dts

@@ -253,6 +253,9 @@
 
 &switch0 {
 	ports {
+		#address-cells = <1>;
+		#size-cells = <0>;
+
 		SWITCH_PORT_SDS(0, 1, 0, qsgmii)
 		SWITCH_PORT_SDS(1, 2, 0, qsgmii)
 		SWITCH_PORT_SDS(2, 3, 0, qsgmii)