policy_hal: handle direct pcm concurrency from different clients

Fallback to non-direct output when direct/track pcm is already
active and clients are not same, since reusing output between
different clients can lead to continuous teardown of sessions
by one client to another.
Force deep-buffer when falling back from direct pcm to non-direct
outputs.

Change-Id: I383b8d526c8a87abe771b3d9d94b2b7c6f7edb6a