[IPV6]: Correct the comment concerning inetsw6 table

It seems that net/ipv6/af_inet6.c was copied from net/ipv4/af_inet.c,
but one comment was not fixed.

Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>