CSD: Add Mel processing for FastMixer

Moved the MelProcessor into the AudioStreamOutSink. This should be ok
now to use in the FastMixer since the new MelProcessor logic is not
blocking and the callbacks are executed asynchronously in the MelWorker.

Test: OboeTester + dumpsys and logs
Bug: 264255998
Change-Id: Idce0a2653b4f8fa42ea12893c6e77e765806f3b1
6 files changed