ASoC: msm: qdsp6v2: append new paths for back-end loopback purpose

Append new paths to allow loopback internally in DSP between PCM
back-ends which are typically mapped to CODEC and BT paths

Change-Id: I8cf492174f0c1b41847d84dd1bafc5a9a26ed11f
Signed-off-by: Patrick Lai <plai@codeaurora.org>