msm_vidc: Update firmware of input buffer count for video encoder

If video firmware is not aware of input buffer count, and driver
queues more buffers than firmware is aware of, this results in
firmware crash. This change updates firmware of updated input buffer
count.

CRs-fixed: 411057
Change-Id: I5713a300636071db80f532029cf81c3b88db0789
Signed-off-by: Ashray Kulkarni <ashrayk@codeaurora.org>