netfilter: conntrack: don't increment invalid counter on NF_REPEAT

netfilter: conntrack: don't increment invalid counter on NF_REPEAT

BugLink: https://bugs.launchpad.net/bugs/1959879
[ Upstream commit 830af2eba40327abec64325a5b08b1e85c37a2e0 ]

The packet isn't invalid, REPEAT means we're trying again after cleaning
out a stale connection, e.g. via tcp tracker.

This caused increases of invalid stat counter in a test case involving
frequent connection reuse, even though no packet is actually invalid.

Fixes: 56a62e2218f5 ("netfilter: conntrack: fix NF_REPEAT handling")
Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Paolo Pisati <paolo.pisati@canonical.com>