ipv6: use flag instead of u16 for hop in inet6_skb_parm

Hop was always either 0 or sizeof(struct ipv6hdr).

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc include/linux/ipv6.h
Simple merge

diff --cc net/ipv6/af_inet6.c
Simple merge

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

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