msm: camera: Fix the cci sequential write issue

  During sequential burst mode, once the queue start executing,
if there is an attempt to load the queue with new command, it
causes ack timeout error.

  Below change ensure that once the queue start executing
we do not load new command until we receive ack for the current
batch. It will be applicable only for sequential burst mode.

Change-Id: I06b6b67b239ddd4c7c0b1cd691ae11a9d3814d97
Signed-off-by: Nishant Pandit <npandit@codeaurora.org>