qcacmn: Move osif priv deallocation to vdev destroy

osif priv is allocated as part of the vdev object and freed as part of
the logical vdev deletion. There is a race condition where in a
component
holding the reference to the vdev is trying to do an operation using
the osif priv. But in the other thread osif priv can be freed.
This can lead to null pointer exception.

Hence, move the osif priv deletion to the vdev physical destroy.
Change-Id: Iea3fd87cb272a51c5691ee2e39a590861c1b1637
CRs-Fixed: 2449996