msm: vidc: add support for loading lowpower bus vectors

When power save mode is enabled the bus values still reflects
the high bandwidth values. Update the bus vectors to reflect
the reduced bandwidth, resulting in power savings.

Change-Id: I4558ad0a2ef54cfbe4f320ce18a02dc013f232cb
Signed-off-by: Ashray Kulkarni <ashrayk@codeaurora.org>