ip-xfrm: support 'proto any' with 'sport' and 'dport'

ip-xfrm: support 'proto any' with 'sport' and 'dport'

When creating an IPsec SA that sets 'proto any' (IPPROTO_IP) and
specifies 'sport' and 'dport' at the same time in selector, the
following error is issued:

"sport" and "dport" are invalid with proto=ip

However using IPPROTO_IP with ports is completely legal and necessary
when one wants to share the SA on both TCP and UDP. One of the
applications requiring sharing SAs is 3GPP IMS AKA authentication.

See also:

 * https://bugzilla.redhat.com/show_bug.cgi?id=497355

Reported-by: Jiří Klimeš <jklimes@redhat.com>
Signed-off-by: Pavel Šimerda <psimerda@redhat.com>