ASoC: msm: Route low latency frontend to in-call music backend

Add routing controls to support routing of low latency stream
to in-call music delivery backend.

Change-Id: I5934f32fb4cbfb7f12a09e9bad76f370c3fd7fb7
CRs-fixed: 550396
Signed-off-by: Narsinga Rao Chella <nrchella@codeaurora.org>