system/core: New stream type and flag for incall music delivery

- Add new stream type and flag for incall music delivery

Change-Id: I54d0d820d2dbb888d2e0cebdca63be2856eb00d8
system/core: Add tunnel format frame size

Add tunnel mode formats frame sizes to audio.h. This ensures frame
size definition in one place.

Change-Id: Ia01cb4cba003e538a53aaa18330ef860367859c1