msm: vidc: Optimize buffer requirements call to HW

Optimize buffer requirements calls to HW to reduce start-up
latency. From now onwards, driver gets output buffer requirements
from HW through sequence event change.

CRs-Fixed: 2055218
Change-Id: Ie676069992d041028158ebf0b7e283e1828b5c9d
Signed-off-by: Praneeth Paladugu <ppaladug@codeaurora.org>