ramips: fix switch setup for ASUS RT-AX53U

The device has only 1 WAN + 3 LAN ports. Remove "lan4" interface
corresponding to the non-existing port.
Signed-off-by: NMatthias Schiffer <mschiffer@universe-factory.net>

target/linux/ramips/dts/mt7621_asus_rt-ax53u.dts

@@ -158,11 +158,6 @@
 			status = "okay";
 			label = "lan3";
 		};
-
-		port@4 {
-			status = "okay";
-			label = "lan4";
-		};
 	};
 };
 

target/linux/ramips/mt7621/base-files/etc/board.d/02_network

@@ -29,6 +29,7 @@ ramips_setup_interfaces()
 		ucidef_set_interface_lan "lan"
 		;;
 	ampedwireless,ally-r1900k|\
+	asus,rt-ax53u|\
 	gehua,ghl-r-001|\
 	h3c,tx1800-plus|\
 	h3c,tx1801-plus|\