cfg80211: always get BSS

Multiple problems were reported due to interaction
between wpa_supplicant and the wext compat code in
cfg80211, which appear to be due to it not getting
any bss pointer here when wpa_supplicant sets all
parameters -- do that now. We should still get the
bss after doing an extra scan, but that appears to
increase the time we need for connecting enough to
sometimes cause timeouts.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Tested-by: Hin-Tak Leung <hintak.leung@gmail.com>,
Signed-off-by: John W. Linville <linville@tuxdriver.com>