drm/msm/a6xx: add build_bw_table for A640/A650

This sets up bw tables for A640/A650 similar to A618/A630, 0 DDR bandwidth
vote, and the CNOC vote. A640 has the same CNOC addresses as A630 and was
working, but this is required for A650 to work.

Eventually the bw table should be filled by querying the interconnect
driver for each BW in the dts, but use these dummy tables for now.

Signed-off-by: Jonathan Marek <jonathan@marek.ca>
Reviewed-by: Jordan Crouse <jcrouse@codeaurora.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>