policy_hal: Support vr audio concurrency

Add support for falling back of VOIP using
FAST + RAW flags to primary output when VR
is going on. This is used to prevent
VOIP from having reverb enabled on it.
Other apps using FAST + RAW are expected
to honor focus

CRs-Fixed: 1099039
Change-Id: Idb2f0d4981b60b1cf8cc0836cb84d38803308ab4