msm: vidc: Add support for session continue

Venus 3x firmware halts execution after raising a
a sequence change event to v4l2 driver. This change
is needed for firmware to resume execution after
it raises a sequence change event.
Before session continue command, the firmware expects
driver to always set the minimum buffer size negotiated
with v4l2 client, and the actual buffer count. Firmware
will use this information to check for buffer sufficiency.

Change-Id: Ib59cfcbdc22008ad842664c722f404f669a23588
Signed-off-by: Arun Menon <avmenon@codeaurora.org>