wil6210: store bss object and use cfg80211_connect_bss()

wil6210: store bss object and use cfg80211_connect_bss()

In a fast disconnect/connect sequence, cfg80211_connect_result() can
fail to find the bss object which the driver is connecting to. Detailed
sequence of events:
* Driver is connected in STA mode
* Disconnect request arrives from user space. Driver disconnects and
  calls cfg80211_disconnected() which adds new event to the
  cfg80211_wq worker thread
* Connect request arrives from user space. cfg80211_connect() stores
  ssid/ssid_len and calls rdev_connect()
* __cfg80211_disconnected() runs in worker thread and zero
  wdev->ssid_len
* Connect succeeds. Driver calls cfg80211_connect_result() which fails
  to find the bss because wdev->ssid_len is zero

To overcome this, upon connect request, store the bss object in the
driver and upon connect completion pass it to kernel using
cfg80211_connect_bss().

Signed-off-by: Dedy Lansky <qca_dlansky@qca.qualcomm.com>
Signed-off-by: Maya Erez <qca_merez@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>