qcacld-3.0: Release vdev reference when sap_get_channel_list failed

If sap_get_channel_list return 0 channel, didn't release vdev reference
acquired by wlan_objmgr_get_vdev_by_macaddr_from_psoc() in function
sap_channel_sel().

Release the vdev reference at the end of function sap_channel_sel().

Change-Id: Ib8d240e464ea893d97fef5f563bfb080646bae46
CRs-Fixed: 2457532