ramips: fix switch for Nexx devices

There are 2 ethernet ports on Nexx WT1520 and WT3020. These ethernet
ports are assigned as follows, and other ports cannot be used.

- WT1520:
  - port0 -> lan
  - port4 -> wan

- WT3020:
  - port0 -> wan
  - port4 -> lan

I dropped ports that cannot be used.

Signed-off-by: INAGAKI Hiroshi <musashino.open@gmail.com>

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

@@ -112,8 +112,6 @@ ramips_setup_interfaces()
 	witi|\
 	wl-wn575a3|\
 	wndr3700v5|\
-	wt1520-4M|\
-	wt1520-8M|\
 	youku-yk1|\
 	zbt-ape522ii|\
 	zbt-we1326|\
@@ -209,8 +207,6 @@ ramips_setup_interfaces()
 	wrtnode|\
 	wrtnode2p | \
 	wrtnode2r | \
-	wt3020-4M|\
-	wt3020-8M|\
 	zbt-wa05)
 		ucidef_add_switch "switch0" \
 			"1:lan" "2:lan" "3:lan" "4:lan" "0:wan" "6@eth0"
@@ -323,7 +319,9 @@ ramips_setup_interfaces()
 		ucidef_add_switch "switch0" \
 			"1:lan" "2:lan" "3:lan" "4:lan" "5:wan" "0@eth0"
 		;;
-	vonets,var11n-300)
+	vonets,var11n-300|\
+	wt1520-4M|\
+	wt1520-8M)
 		ucidef_add_switch "switch0" \
 			"0:lan" "4:wan" "6@eth0"
 		;;
@@ -356,6 +354,11 @@ ramips_setup_interfaces()
 		ucidef_add_switch "switch0" \
 			"1:lan" "2:lan" "0:wan" "6@eth0"
 		;;
+	wt3020-4M|\
+	wt3020-8M)
+		ucidef_add_switch "switch0" \
+			"4:lan" "0:wan" "6@eth0"
+		;;
 	zbtlink,zbt-we1226|\
 	y1)
 		ucidef_add_switch "switch0" \