Voltage Control: initial voltage control for MSM S4-Pro SOC

Signed-off-by: Paul Reioux <reioux@gmail.com>
Voltage Control: add sysfs interface

Signed-off-by: faux123 <reioux@gmail.com>
random: add tracepoints for easier debugging and verification

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>