qcacmn: VDEV MLME component changes

1) replace legacy string with ext
2) Added new compile CMN_VDEV_MLME_CMPT_ENABLE macro for
   VDEV MLME component

Change-Id: I75fc7cbae9c437d60e666f0c188fb63e98fdac3b
CRs-Fixed: 2307722
5 files changed