suggested patches for netinet6/

[Jun-ichiro itojun Hagino]

> >> > + nd6_nud_hint() is only called as nd6_nud_hint(NULL, NULL, 0);
> >> >   in some cases from netinet/tcp_input.c
> >> >   With these args, the routine is a NOP. I propose to remove it
> >> >   (and the associated field, ln_byhint, in struct llinfo_nd6)

	on other OSes we call nd6_nud_hint() in a useful way.  please do not
	remove it. (more diffs between OSes = more pain for us)

itojun