drm/msm/sde: delay inline rotate start until kickoff

Avoid sending the inline rotate start until the actual hardware
kickoff is dispatched. This prevents the rotator driver from
detecting a false timeout while the DRM driver is waiting for
the previous frame to complete.

Change-Id: I8df2ecb2cb245401f357d8082f16e30452c26574
Signed-off-by: Clarence Ip <cip@codeaurora.org>