Undervolt: add checks to disallow too extreme voltages, min and max.

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
krait: remove boost module that added 25mV on every step for core... oh well.

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
krait: show also PVS table name in proc API
krait: added 162MHz and 270MHz step - thanks to n3ocort3x