mali: GPU control for r3p2 mali

GPU frequency, scaling and voltage control.
Based on netarchy's initial implementation and improvements of gokhanmoral and
ported onto the pegasus-m400 / Galaxy.

credits to Netarchy, Gokhanmoral, AndreiLux, DerTeufel

Slightly adjusted by andip71

Conflicts:
	drivers/gpu/mali400/r3p2/mali/platform/pegasus-m400/exynos4_pmm.c