drm: define a new SDE custom IOCTL for early wakeup display feature

Add this new IOCTL for user-space to wake up kernel display as soon
as it gets a new frame update.

Change-Id: Icd45b47e99ca0ea996e46ae8335a29f6636bf406
Signed-off-by: Lei Chen <chenlei@codeaurora.org>