Support setting preferred mixer attributes for USB devices.

This is part of USB audio improvement. With setting mixer attributes,
apps will be able to choose the best mixer attributes for their
playback. This can help improve latency and audio experience.

Bug: 239435816
Test: atest AudioManagerTest
Test: atest audiopolicy_tests
Test: Manually
Change-Id: Ifd1e8e35f94dab309eabe879d20ae0358038a4bf