msm: bam_dmux: configure satellite mode via devicetree

Add support to allow satellite mode configuration of the BAM hardware
via device tree.  Satellite mode is only used on specific targets where
shared access of the BAM is possible.

Change-Id: I6ac4e2ad7827b5651034651d18cf716324462d0f
Signed-off-by: Jeffrey Hugo <jhugo@codeaurora.org>