msm: vidc: Update clock selection algorithm

    - Update operating rate for each session based on current
          snapshot of all concurrent instances.
    - Move clock related variables to single struct.
    - Misc bug fixes in quality mode.
    - Add\Remove NULL checks in clock scaling code.
    - Update debugfs support according to new design.
    - Fix issue in clock calculation.
    - Init clock states at instance state transistions so
          that they finish faster.

CRs-Fixed: 2012520
Change-Id: I7fd167d91b96d70e582d1f353ae68ff30439849f
Signed-off-by: Praneeth Paladugu <ppaladug@codeaurora.org>