qcacmn: Get vdev ref only if after vdev is in created state

In function wlan_tdls_antenna_switch is getting the vdev ref
without checking the vdev state. Get vdev ref only, if it is
in created state.

Use api wlan_objmgr_vdev_try_get_ref to get vdev ref.

Change-Id: Ie3c324f39cfb105dbb853ce3caf1a6be6107ca67
CRs-Fixed: 2392838