dmaengine: qcom_bam_dma: Add support for BAM v1.7.0

Add register offset table entry for the newer (v1.7.0) version of the BAM IP
found on MSM8916. Update the DT bindings documentation.

Signed-off-by: Archit Taneja <architt@codeaurora.org>
Tested-by: Ivan T. Ivanov <iivanov@mm-sol.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>