msm: vidc: enable minimum bus vote

In msm8939, MM NOC default voting from SMMU driver side has been removed.
It is individual client responsibility to vote for bus before any DDR
transactions are initiated. when client calls vote bus with load of 0,
it is translating to an unvote_bus causing DDR transactions to fail.
Since it is target specific, added control to vote minimum bus bandwidth.

Change-Id: I246180c3e32ea791f6f7fc79d3796b0b873b4c2d
Signed-off-by: Srinu Gorle <sgorle@codeaurora.org>