msm: camera: Add support for dynamic bus scaling

ISP bus vector should be calculated based on input
data rate and output dimensions. The vectors will
be dynamically changed based on the ISP output
enabled.

Change-Id: I7cbbf8fc5231b64a91c61cc7a2136bf8c09a730a
Signed-off-by: Kevin Chan <ktchan@codeaurora.org>