[patch] ipw2100: support WEXT-18 enc_capa v3

This patch allows ipw2100 driver to advertise the WPA-related encryption
options that it does really support.  It's necessary to work correctly
with NetworkManager and other programs that actually check driver & card
capabilities.

Signed-off-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>