[PATCH] wireless/ipw2200: support WE-18 WPA enc_capa

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: John W. Linville <linville@tuxdriver.com>