wireless: make wireless drivers select core

It is somewhat non-sensical to allow selecting wireless
drivers without showing wireless core code options, and
since the wext refactoring this has made it possible to
generate configurations that will not build. Avoid this
and make wireless drivers select the wireless options.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>