Telephony: CDMA - Handle call collision scenarios

There can be 2 types of call collisions
    - Modem/RIL dropping an existing call and replace it with
      another one with the same call id (index)
    - Modem/RIL, after ending the previous call, reports the new
      call with a different call id
Both these above cases have been handled to avert undesirable
behavior at telephony layer.
CRs-Fixed: 453390

Change-Id: I65d8d941ccec63be754ca79c36bef34618fb1fb1