msm: kgsl: Power Optimizer Push-Pop

A new feature for GPU power saving.  Using the output of normal
GPU DCVS delicately try pushing to a slightly lower than recommended
power level.  Pop up immediately if the lower level is non-sustainable.
Use statistic shaping to the point of DDR increase to help maintain
the lower GPU frequency.

Change-Id: I38c187aaf52114664ccea27b2cc3637cd0fd366f
Signed-off-by: Lucille Sylvester <lsylvest@codeaurora.org>