WNM: Optimize a single BSS transition management candidate scan

WNM: Optimize a single BSS transition management candidate scan

If the BSS Transition Management Request frame includes only a single
candidate and we need to scan for the BSS to get up-to-date information,
use a scan for the known BSSID instead of wildcard BSSID. In addition,
set the SSID in the scan if it is known based on old scan results in the
BSS table. This removes unnecessary Probe Response frames when we are
interested in results from only a single BSS.

Signed-off-by: Jouni Malinen <jouni@qca.qualcomm.com>