wireless: add back sysfs directory

wireless: add back sysfs directory

commit b33cfe21479f50dce8b411571fb6e63a7cea9815 broke (at least)
Fedora's networking scripts, they check for the existence of the
wireless directory. As the files aren't used, add the directory
back and not the files. Also do it for both drivers based on the
old wireless extensions and cfg80211, regardless of whether the
compat code for wext is built into cfg80211 or not.

Cc: stable@vger.kernel.org [3.6]
Reported-by: Dave Airlie <airlied@gmail.com>
Reported-by: Bill Nottingham <notting@redhat.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>