Revert "Revert "Voltage Control: initial voltage control for MSM Snapdragon 800 SOC""

This reverts commit 9ec54a27e64c3396a0cca7bc20d9c398c2952fef.
Revert "Revert "Voltage Control: add sysfs interface""

This reverts commit 19f44830f54da072bd766d0d68536660952d4837.
Revert "Revert "Voltage Control: allow for lower minimums""

This reverts commit 04e95a2324788b297aebd93b9caefba32c4118c7.
Update

Change-Id: Ia082a2cb59ee935ec6def31f62d2fda81f2fa1f2