policy_hal: fix improper voice-playback concurrency handling

- setPhoneState checks call-state in audio hal to filter out
  unworthy usage of this API.
- With M upgrade, change to update call-state with audio hal is
  removed, instead permission checks are introduced to prevent
  random usage of such APIs. But setPhoneState is still checking
  for this call-state causing improper concurrency handling.
- Fix the issue by removing state check from setPhoneState.
- Remove set and get for parameter "in_call" from voice_extn.

Change-Id: I92fe10c617d6158976a0e07eed3275acb0aadd15