netfilter: ipvs: Remove useless ipvsh param of frag_safe_skb_hp

The param of frag_safe_skb_hp, ipvsh, isn't used now. So remove it and
update the callers' codes too.

Signed-off-by: Gao Feng <gfree.wind@vip.163.com>
Acked-by: Simon Horman <horms+renesas@verge.net.au>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>