msm: vidc: Set OUTPUT2 dimension along with downscalar property

Venus FW expects OUTPUT2 dimensions when downsclar property is set.
When the dimensions are not set Venus doesn't have enough information
to return buffer requirements to the driver, so it asserts out. Hence
setting the OUTPUT2 dimensions with downscalar property.

CRs-Fixed: 750727
Change-Id: I33c1b805ef328eac40f1d09362268e59137f900a
Signed-off-by: Praneeth Paladugu <ppaladug@codeaurora.org>