Telephony: Set data registration state in APM for IWLAN RAT

- APM causes data registration state to be POWER_OFF. Set it
  to IN_SERVICE for iwlan case
- In APM, UNSOL_VOICE_NETWORK_STATE_CHANGED resets data RAT and
  registration state to POWER_OFF. Ensure that this is done only
  when current RAT is not IWLAN or when iwlan feature is not
  available.

CRs-Fixed: 754338

Change-Id: I4c9bff1663837530349cb53027e2ef9b7dc873d6