lantiq: move common DSL setup into lantiq.sh

DSL setup consists of the same commands for all subtargets, so move it
into a helper function.

While at it, remove shebang from library file.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>

target/linux/lantiq/base-files/lib/functions/lantiq.sh

@@ -1,5 +1,18 @@
-#!/bin/sh
-
 lantiq_is_vdsl_system() {
 	grep -qE "system type.*: (VR9|xRX200)" /proc/cpuinfo
 }
+
+lantiq_setup_dsl_helper() {
+	local annex="$1"
+
+	ls /lib/modules/$(uname -r)/ltq_atm* 1> /dev/null 2>&1 && \
+		ucidef_add_atm_bridge "1" "32" "llc" "bridged" "dsl"
+
+	if lantiq_is_vdsl_system; then
+		ucidef_add_vdsl_modem "$annex" "av"
+	else
+		ucidef_add_adsl_modem "$annex" "/lib/firmware/adsl.bin"
+	fi
+
+	ucidef_set_interface_wan "dsl0" "pppoe"
+}