msm: vidc: Add support for decoder dynamic clock scaling

Add support for dynamic clock scaling by calculating the
decoding fps. Fps is calculated using input timestamps.

CRs-fixed: 405399
Change-Id: I0f09d902a3d44a9b93540ed652f872baf8ef8264
Signed-off-by: Praneeth Paladugu <ppaladug@codeaurora.org>
Signed-off-by: Ashray Kulkarni <ashrayk@codeaurora.org>
Signed-off-by: Vinay Kalia <vkalia@codeaurora.org>