vidc: upgrade video core clock rate based on time taken to decode a frame

Currently video clock rate is set based on the resolution
and fps of the given clip. But some clips have a high bit
rate for a given resolution which causes high decode time.
Changes were made to consider frame decode time and upgrade
the clock rate accordingly

CRs-fixed: 346580
Change-Id: Ie89a736eb9f93286486ae7688633a828c7415fd2
Signed-off-by: Mohan Kumar Gubbihalli Lachma Naik <mgubbi@codeaurora.org>