realtek: remove wrong SMI bus from XGS1250

The RTL930x have only 4 SMI busses (0-3) and the XGS1250 SFP port ist
directly managed. Remove the wrong configuration in the dts.

Signed-off-by: Markus Stockhausen <[email protected]>
Link: https://github.com/openwrt/openwrt/pull/16457
Signed-off-by: Robert Marko <[email protected]>

target/linux/realtek/dts/rtl9302_zyxel_xgs1250-12.dts

@@ -310,7 +310,6 @@
 			compatible = "ethernet-phy-ieee802.3-c22";
 			phy-is-integrated;
 			reg = <27>;
-			rtl9300,smi-address = <4 0>;
 			sds = < 9 >;
 		};