msm: camera: cpas: Change to enable bus scaling for AHB

This change scales BW voting with src clock voltage corner.
Adds a debugfs to disable this scaling.

CRs-Fixed: 2531856
Change-Id: I266e34ca81f635954e60648366bcc4792f90fdb6
Signed-off-by: Karthik Anantha Ram <kartanan@codeaurora.org>