netfilter: nf_conntrack: ct_cpu_seq_next should increase position index

If .next function does not change position index,
following .show function will repeat output related
to current position index.

Cc: stable@vger.kernel.org
Fixes: 1f4aace60b ("fs/seq_file.c: simplify seq_file iteration code ...")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=206283
Signed-off-by: Vasily Averin <vvs@virtuozzo.com>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>

net/netfilter/nf_conntrack_standalone.c

@@ -411,7 +411,7 @@ static void *ct_cpu_seq_next(struct seq_file *seq, void *v, loff_t *pos)
 		*pos = cpu + 1;
 		return per_cpu_ptr(net->ct.stat, cpu);
 	}
-
+	(*pos)++;
 	return NULL;
 }