Add faux Simple GPU gov

Conflicts:
	drivers/gpu/msm/kgsl_pwrscale_trustzone.c
KGSL: make simple govenor a selectable option, co-exist with ondemand

Conflicts:
	drivers/gpu/msm/kgsl_pwrscale_trustzone.c
KGSL: simple governor: expose tunables to sysfs interface via module_param
KGSL: Simple Governor: fix minor logic issue
KGSL: Simple Governor: some styling changes, early returns
KGSL: Simple Governor: so I kinda butchered in a good way of course the original code from faux, but the simplicity is still here. Added an history so that we can track the average do that the frequency scaling is much more proporcional to the actual GPU load rather than having is ramp up every now and then due to spurious load spike. Also remove two useless ifs.
Fix typo in simple GPU governor addition