Use ipsec6_in_reject() to simplify ip6_ipsec_fwd() and ip6_ipsec_input().
ipsec6_in_reject() does the same things, also it counts policy violation
errors.

Do IPSEC check in the ip6_forward() after addresses checks.
Also use ip6_ipsec_fwd() to make code similar to IPv4 implementation.

Obtained from:	Yandex LLC
Sponsored by:	Yandex LLC


git-svn-id: svn+ssh://svn.freebsd.org/base/head@275715 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f
Do not count security policy violation twice.
ipsec*_in_reject() do this by their own.

Obtained from:	Yandex LLC
Sponsored by:	Yandex LLC


git-svn-id: svn+ssh://svn.freebsd.org/base/head@275716 ccf9f872-aa2e-dd11-9fc8-001c23d0bc1f