Revert "DeviceSettings: Add Performance menu and only GPU freqs for now"

This reverts commit ed7b392d402137d376013566eda1df72632e89d3.

This wasn't working because I set the wrong max_gpuclk pathc.
But we are using PerformanceControl now so added a new GPU tab there with proper OC setting

Change-Id: Ia31b0db199dd8308d97352e9ad970b40bb4bebd5
Merge "Revert "DeviceSettings: Add Performance menu and only GPU freqs for now"" into jb-mr2