Support volume-changed sounds on master-volume-only configs

Some products manipulate only the master volume, and the existing
code does not play volume-change tones when the master volume
is adjusted.  This CL includes some config-driven behavior that
will play those tones (via the system stream) if desired.

Bug 6498986

Change-Id: I2415773325d0a0039efc67897bc371b1f2e18063