Certain type of hardware, for example wl1251 and wl1271, need a template
for the Probe Request. Create a function ieee80211_probereq_get() which
creates the template and drivers send it to hardware.
Signed-off-by: NKalle Valo <kalle.valo@nokia.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>