msm: vidc: Venus HW power optimizations

    - Remove unnecessary sleep after clock disable.
    - Change HW poll logic to less time and more number of
        times vs more time and less number of times.

CRs-Fixed: 2012520
Change-Id: I6030655d7c6bff325b7d4a6dbb1f8943d44bb986
Signed-off-by: Praneeth Paladugu <ppaladug@codeaurora.org>