drm/msm/sde: Increase command mode idle timeout in early wake-up

Sometimes updates from framework comes with slight delay after
early wake up. In such case prevent clock switch off to avoid
frame miss or jank in next update. So, increase the command
mode idle timeout sufficiently to prevent such issue.

Change-Id: I4c92f3cfca5402ee9f6ee29beaf7a32506ac92c7
Signed-off-by: Jayant Shekhar <jshekhar@codeaurora.org>