msm: kgsl: Schedule adreno_start in a high priority workqueue

Better safe than sorry. Also, return early if we didn't set a _wake_timeout.

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
Signed-off-by: Blechd0se <alex.christ@hotmail.de>
Resotre original qcom way for enable/disable display