platform: msm: dt-bindings: Add USB BAM driver bindings

Add bindings for USB BAM driver which allows USB BAM to
communicate with other peripherals' (e.g. QDSS or IPA) BAM.

Change-Id: I88fc14076b8b502be4b248ea4874f11b34cea2d5
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>