qcacmn: Add NULL check for wdev member of vdev's ospriv
Add NULL check for access to wdev.
There could be cases where the wdev could not we initialized
to appropriate values, so we should have a NULL check before
we access its members.
CR's Fixed: 2168374
Change-Id: Id0a3f9b64c5e9beed86f5a3c019a5fe5dbdb8bd7