ipvs: Pass ipvs into ip_vs_in_icmp and ip_vs_in_icmp_v6

With ipvs passed into ip_vs_in_icmp and ip_vs_in_icmp_v6
they no longer need to call the hack that is skb_net.

Additionally ipvs_in_icmp no longer needs to call dev_net(skb->dev)
and can use the ipvs->net instead.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Simon Horman <horms@verge.net.au>