PM / devfreq: add msm-adreno-tz governor

This governor can be used to control adreno GPUs.
It is unlikely to be useful for other devices.

Change-Id: Icf481322454b814d2f41019f2f01286062409952
Signed-off-by: Jeremy Gebben <jgebben@codeaurora.org>
Signed-off-by: Vladimir Razgulin <vrazguli@codeaurora.org>