msm: vidc: Overwrite max mbs per frame value in driver

Currently Venus is returing incorrect max mbs per frame
values. Hence update this value in driver with proper
values. This change will be reverted once Venus issue
is fixed.

Change-Id: Ibf9bf4630ab1692ecc5be242da3da620233aaa2b
Signed-off-by: Praneeth Paladugu <ppaladug@codeaurora.org>