[audio] fix request/response types

TEST: none needed
Change-Id: Ib9d09725081e42b6f4a30f31e4f6c3bedad7638e

[audio][drv][proto] Update the audio stream driver protocol.

Add the following...

++ The ability to report and control HW AGC capabilities.
++ The ability to report a persistent unique identifier for a stream.
++ The ability to report strings which may be fetched from hardware
and useful for either debugging or UIs. Currently defined strings
include manufacturer and product IDs.

Test: Build only
Change-Id: I2fdca98469aa6edcb3cd7b2ceed4dc5d96236f5a

[ulib][audio-driver-proto] Move audio driver audio-proto code to a static library

Change-Id: Icc9c6c8ad755ca781fb8669f7cd4a8a5d3df9d32