Remove disconnected APs from BSS table if likely out-of-range

Remove disconnected APs from BSS table if likely out-of-range

In some cases, after a sudden AP disappearing and reconnection to
another AP in the same ESS, if another scan occurs, wpa_supplicant might
try to roam to the old AP (if it was better ranked than the new one)
because it is still saved in BSS list and the blacklist entry was
cleared in previous reconnect. This attempt is going to fail if the AP
is not present anymore and it'll cause long disconnections.

Remove an AP that is probably out of range from the BSS list to avoid
such disconnections. In particular mac80211-based drivers use the
WLAN_REASON_DISASSOC_DUE_TO_INACTIVITY reason code in locally generated
disconnection events for cases where the AP does not reply anymore.

Signed-off-by: David Spinadel <david.spinadel@intel.com>