brcm63xx: board.d: request untagged switch config where applicable

In order to prepare support for generating tagged switch configurations by
default, explicitely request untagged configs for boards which do not already
request tagging to retain default behaviour.

Signed-off-by: Jo-Philipp Wich <jo@mein.io>

target/linux/brcm63xx/base-files/etc/board.d/02_network

@@ -33,7 +33,7 @@ fast2604 |\
 rta1320 |\
 v2110)
 	ucidef_add_switch "switch0" \
-		"0:lan:4" "1:lan:3" "2:lan:2" "3:lan:1" "5@eth0"
+		"0:lan:4" "1:lan:3" "2:lan:2" "3:lan:1" "5u@eth0"
 	;;
 
 agpf-s0 |\
@@ -57,7 +57,7 @@ usr9108 |\
 v2500v_bb)
 	ucidef_set_interfaces_lan_wan "eth1" "eth0"
 	ucidef_add_switch "switch0" \
-		"0:lan:4" "1:lan:3" "2:lan:2" "3:lan:1" "5@eth1"
+		"0:lan:4" "1:lan:3" "2:lan:2" "3:lan:1" "5u@eth1"
 	;;
 
 dsl-274xb-c |\