wdev->current_bss is not updated for a non-assoc link STA vdevs.
As a result, a WARN_ON error is seen in cfg80211_ch_switch_notify()
when it’s called for non-assoc link.
To resolve this, update the wdev->current_bss for non-assoc links
as part of connection and clean up this as part of disconnection.
Change-Id: I5020200fb927dd72d2e1bf0ed73e7a5750897619
CRs-Fixed: 3618438