msm: vidc: Correct buffer counts for secondary output mode

The buffer counts in driver are not proper if client enables
multi stream secondary output mode resulting in video failures.
Correct the buffer counts to resolve the failures.

Change-Id: Ia3707f858c58db6bd3ca1176c98f9c529cc5b181
Signed-off-by: Maheshwar Ajja <majja@codeaurora.org>