qcacld-3.0: Takecare to stop and down vdev in monitor mode

In monitor mode there is no disconnect, so vdev stop and down is
not handled. Make sure to stop and down the vdev before vdev delete.

Change-Id: I25f5a0e01deda8f2e16e102113b10f32e89b3e38
CRs-Fixed: 2357047
1 file changed