qcacmn: Use after free when clean up scan queue

When invoked wlan_cfg80211_cleanup_scan_queue, it will try to clean
up pending scan requests in queue from kernel. However, when the
netdevice is down, this request could be already freed by kernel.
To fix this issue, also add the pointer to netdevice in scan_req
so what we can check the status of netdevice in scan_req instead
of cfg80211_scan_request which might already be freed for this case.

Change-Id: I6189c52b638bc4f408e4d4c694c178c7d2f3de52
CRs-Fixed: 2164404
2 files changed