[PATCH] prism54: update to WE-19 for WPA support

Add WE-19 capabilities to prism54 fullmac driver so that it supports the
necessary Wireless Extensions WPA calls.  Convert reporting of WPA/RSN
Generic Information Elements to IWEVGENIE rather than pre-WE-19
IWEVCUSTOM as well.

Signed-off-by: Dan Williams <dcbw@redhat.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>