lantiq: remove includes of non-existent /lib/functions/lantiq.sh

lantiq.sh is still included in files which do not use it anymore.
Remove the includes.

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

target/linux/lantiq/base-files/etc/uci-defaults/02_migrate_xdsl_iface

@@ -1,7 +1,6 @@
 #!/bin/sh
 
 . /lib/functions.sh
-. /lib/functions/lantiq.sh
 
 IFNAME_CHANGED=0
 

target/linux/lantiq/base-files/lib/preinit/05_set_preinit_iface_lantiq

@@ -1,7 +1,5 @@
 #!/bin/sh
 
-. /lib/functions/lantiq.sh
-
 set_preinit_iface() {
 	ifname=eth0
 }