drm/msm/sde: delay inline rotation clock drops by one commit

Avoid acting on reduced rotator clocks for inline rotation
use cases until the next commit cycle. This allows the
hardware to complete the current commit using the previous,
higher, clock setting and avoids potential underruns due
to prematurely reduced rotator clock speeds.

Change-Id: If85905ef9a3f67dc71288aeabaf2b52d5dd5b768
Signed-off-by: Clarence Ip <cip@codeaurora.org>