voltage_control: initial voltage control for 8960 krait
based on the voltage control patch for s4 pro socs by @faux123

Signed-off-by: Dennis Rassmann <showp1984@gmail.com>
Voltage Control: add sysfs interface
Signed-off-by: faux123 <reioux@gmail.com>
Signed-off-by: Dennis Rassmann <showp1984@gmail.com>
defconfig: enable user voltage table (sysfs)

Signed-off-by: Dennis Rassmann <showp1984@gmail.com>