netfilter: xt_recent: Fix attempt to update deleted entry

When both --reap and --update flag are specified, there's a code
path at which the entry to be updated is reaped beforehand,
which then leads to kernel crash. Reap only entries which won't be
updated.

Fixes kernel bugzilla #207773.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=207773


Reported-by: Reindl Harald <h.reindl@thelounge.net>
Fixes: 0079c5ae ("netfilter: xt_recent: add an entry reaper")
Signed-off-by: Jozsef Kadlecsik <kadlec@netfilter.org>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>