The netdev of link-local address cannot be auto decided, and the link-local address should always be reguarded as address on local network.
The problem we met:
When using `icmpv6_autoconfig` with multiple netdev, the `icmpv6_neighbor` may take out wrong netdev with ip address already set, then it may send solicitation with wrong address (`dev->d_ipv6draddr`) on wrong device, and regard the link-local address as conflict (because `dev->d_ipv6draddr` exists on this network).
Signed-off-by: Zhe Weng <wengzhe@xiaomi.com>
d98bfc3e49