tegra: custom user voltage control (thansk faux123)

-also some voltage tweaks and debugging statement tweaks

Conflicts:

	arch/arm/mach-tegra/tegra3_dvfs.c
Voltage Control tweak - let's ignore the highest freq slot for show and
save since it shows 1.6GHz twice in the voltage table in System Tuner.
We are are only allowing 1200mV for 1.6, so the top slot is not
currently used.