ath6kl: Configure probed SSID list consistently

Set max_scan_ssids and max_sched_scan_ssids to same value. These use the
same probed SSID list, so there is no point in using different maximum
number of SSIDs.

Clear probed SSID entries that are not used. This was already done for
sched_scan, but not for scan. Be consistent and clear the table for both
cases to avoid leaving bogus entries.

In addition, share the same function for setting the probed SSIDs for
scan and sched_scan paths. This fixes setting of wildcard SSID flag
(ANY_SSID_FLAG) and changes the scan path to use probed SSID index
consistently (i.e., start with 0 similarly to sched_scan; firmware
will handle the needed internal mapping).

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