PM: devfreq: Fix simple_ondemand crashing on startup

simple_ondemands private data must be set to NULL, otherwise we would
run into a NULL pointer in kgsl_devfreq_get_dev_status().

Change-Id: I6cc6a8b11e3b58b8c3e3c26d43ee36949cf62351
PM: devfreq: Report correct GPU frequency in sysfs

Change-Id: I5f6f3ec8a4c77befa15df678842c242a68474446
Disable gboost by default for now on Slim Governor

Change-Id: I92a8c44e4ffdba0ac7f6fa671cfeca508633546f
Signed-off-by: RobbieL811 <RobbieLancaster811@gmail.com>