msm: vidc: Update core and stage selection logic

Update logic that decides number of cores, workmode,
and calculates load to consider few more parameters.

CRs-Fixed: 2091112
Change-Id: I0066b58a894733f589ecf9d6ccb99b2d751bc93e
Signed-off-by: Saurabh Kothawade <skothawa@codeaurora.org>