Revert adding Voltage Control

lets better not do that, for safety reasons.

Revert "Voltage Control: allow for lower minimums"

This reverts commit 00b5fe469bcda9c9407a648c54444151bb04470d.

Revert "Voltage Control: add sysfs interface"

This reverts commit 82b4c2a41ee208a53c8b72db055eb13f50476fbd.

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

This reverts commit ef9c7110a272502187442d2f61860435247ce342.

Change-Id: I9cb1ed08ffb3fecc4dbedac7acf90402ac26630d