MLD STA: Use AP MLD address as previous BSSID for reassociation requests
The Linux kernel expects to use the AP MLD address in
NL80211_ATTR_PREV_BSSID for reassociation requests when the current
association is MLO capable.
Previously, wpa_supplicant was using the BSSID value in
NL80211_ATTR_PREV_BSSID even if the connection is MLO capable. Fix this
by sending the AP MLD address in NL80211_ATTR_PREV_BSSID for
reassociation requests when MLO is used.