audio: Manage audio focus for QCHAT

- Cherry-picked from the commit with commit ID:
c14c6156e879ec1c3f83f6a2cc31dac1d22147a2
- FR-fixed: 8965

Change-Id: I51c554b82c6177b7d3e845bdc8970825b5d1198a
frameworks/base: Add support for QCHAT call.

- Add VSID for QCHAT.
- Add a key which can be used with getParameters()
to query all call states.

Change-Id: If7be9467013700b220c9b10c6236a99d56f7a8cc