msm: vidc: Provide the correct buffer count to client

If DCVS is active, we add extra output buffers and update the firmware
accordingly.  However we don't update the client with the extra buffer
count.  This commit updates the client accordingly.

In addition, this patch acts as a workaround for a firmware bug (will be
fixed independently), where the firmware refuses to start unless it owns
all the output buffers.  Since the firmware buffer count > client buffer
count, client will never actually provide all the buffers required for
the firmware to start.

Change-Id: Ie9b022e37d0654a761f7c7a95a8180b7fda0e418
Signed-off-by: Deva Ramasubramanian <dramasub@codeaurora.org>