soc: qcom: bam_dmux: Add Bam dmux drivers support

This is a snapshot of the BAM DMUX driver as of msm-3.18
commit <49f87c56e6f2> (Merge "ASoC: msm8952: Add more dai links to support
compress capture").

Bam dmux driver provides support for multiple clients to send/receive data
faster to modem by using single A2-BAM physical connection.

CRs-Fixed: 2144615
Change-Id: I39b7a9b1df014cfbe6df1aba0f67a25ad1d47318
Signed-off-by: Arun Kumar Neelakantam <aneela@codeaurora.org>