neigh: Don't require dst in neigh_hh_init

- Add protocol to neigh_tbl so that dst->ops->protocol is not needed
- Acquire the device from neigh->dev

This results in a neigh_hh_init that will cache the samve values
regardless of the packets flowing through it.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc include/net/neighbour.h
Simple merge

diff --cc net/core/neighbour.c
Simple merge

diff --cc net/decnet/dn_neigh.c
Simple merge

diff --cc net/ipv4/arp.c
Simple merge

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