mali/midas-power: Decrease minimum voltage boundary

mali:
Decrease minimum voltage initialisation data for MAX77686 on buck3 rail / vdd_g3d to minimum value as defined in regulator driver.
Decrease minimum voltage soft-limit in GPU voltage control to same value.

midas-power.c: Adjust min/max voltages of several regulators to properly support undervolting

Conflicts:
	arch/arm/mach-exynos/mach-smdk4x12.c
	arch/arm/mach-exynos/midas-power.c