busybox

udhcp6: read_interface should save link-local ipv6 address

Patch is based on work by tiggerswelt.net. They say:
"Using this patch it was no problem to acquire an IPv6-Address via DHCPv6
using ISC DHCPD6 on server-side."

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>