msm: camera: icp: Use usleep instead of msleep for smaller delays

usleep is more precise for smaller sleep times compared to msleep,
hence using it to ensure reduced latency while disabling A5.

Change-Id: I92eeff65caaa3b0739e2df7ca7ec12eecea9638d
Signed-off-by: Karthik Anantha Ram <kartanan@codeaurora.org>