msm: vidc: decide batching while configuration

driver returns min buffer count to client which includes
extra buffers count which is required for batching even
though batching may be disabled in start_streaming() later.
So decide batching in set format (configuration) to avoid
adding extra buffers count to reduce memory usage in
non-batching cases.

Change-Id: I147f7aaf928074a23c9dcda2dbf69a744cec382d
Signed-off-by: Maheshwar Ajja <majja@codeaurora.org>