ASoC: msm: qdsp6v2: Update the routing for aux pcm usecase

Audio can be looped back between primary and secondary aux pcm
for some of the usecases.
Change adds routing table entry and support for allowing loopback.

Change-Id: I33754dac4c88dac3daa2a0d34fcd9a7d9d7d1f4a
CRs-fixed: 495000
Signed-off-by: Gopikrishnaiah Anandan <agopik@codeaurora.org>