audio: derive sound device for concurrent playback usecases

When a new playback usecase has to be started, existing playback
usecases might have to be re-routed (or not) to the new device
based on usecase requirements or h/w limitations
(e.g headphones and speaker sharing the same backend).

This change addresses this requirement by deriving the
new device based on pre-defined cases.

CRs-Fixed: 1077122
Bug: 31671778
Change-Id: Ic0fd4e8d2c1119e7198dc5bb5e5a51817f0110c1