msm: kgsl: Introduce simple GPU governor

Not to be confused with faux123's simple GPU algorithm.
This governor is the port of the updated conservative governor.

It is based on the trustzone policy and the simple GPU algorithm.

Signed-off-by: Zhao Wei Liew <zhaoweiliew@gmail.com>
ghost: Use simple governor

Signed-off-by: Zhao Wei Liew <zhaoweiliew@gmail.com>