cfg80211: hold bss_lock while updating nontrans_list

Synchronize additions to nontrans_list of transmitting BSS with
bss_lock to avoid races. Also when cfg80211_add_nontrans_list() fails
__cfg80211_unlink_bss() needs bss_lock to be held (has lockdep assert
on bss_lock). So protect the whole block with bss_lock to avoid
races and warnings. Found during code review.

Fixes: 0b8fb823

 ("cfg80211: Parsing of Multiple BSSID information in scanning")
Signed-off-by: Rameshkumar Sundaram <quic_ramess@quicinc.com>
Link: https://lore.kernel.org/r/1649668071-9370-1-git-send-email-quic_ramess@quicinc.com
Signed-off-by: Johannes Berg <johannes.berg@intel.com>