qcacld-3.0: Don't Update limMlmState in invalid state in set key resp

In case set key is sent to firmware and Roaming updated the session
before set key resp is processed in LIM, the limPrevMlmState will
be 0 and thus updating limMlmState to limPrevMlmState will result
in improper limMlmState, leading to sync issue.

So do not update the limMlmState in invalid state in set key resp.
Also update limPrevMlmState to limMlmState during roaming.

Change-Id: I96291e7c3eb34df8b5741745448c76cf63b1f200
CRs-Fixed: 2574731