ipv6: ndisc: Convert to dst_neigh_lookup()

Now all code paths grab a local reference to the neigh, so if neigh
is not NULL we unconditionally release it at the end.  The old logic
would only release if we didn't have a non-NULL 'rt'.

Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc net/ipv6/ndisc.c
Simple merge