netfilter: nf_ct_expect: nf_ct_expect_related_report(): Return zero on success.

Commit 4dee62b1 ("netfilter: nf_ct_expect: nf_ct_expect_insert()
returns void") inadvertently changed the successful return value of
nf_ct_expect_related_report() from 0 to 1, which caused openvswitch
conntrack integration fail in FTP test cases.

Fix this by always returning zero on the success code path.

Fixes: 4dee62b1 ("netfilter: nf_ct_expect: nf_ct_expect_insert() returns void")
Signed-off-by: NJarno Rajahalme <jarno@ovn.org>
Acked-by: NJoe Stringer <joe@ovn.org>
Signed-off-by: NPablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nf_conntrack_expect.c

@@ -467,7 +467,7 @@ int nf_ct_expect_related_report(struct nf_conntrack_expect *expect,
 
 	spin_unlock_bh(&nf_conntrack_expect_lock);
 	nf_ct_expect_event_report(IPEXP_NEW, expect, portid, report);
-	return ret;
+	return 0;
 out:
 	spin_unlock_bh(&nf_conntrack_expect_lock);
 	return ret;