Add Smooth Display option to developer in Settings

Force to the highest refresh rate.

Bug: 137064289
Test:$ adb root
$ adb shell "echo 1 > /d/tracing/events/sde/enable"
$ adb shell "echo 1 > /d/tracing/tracing_on"
$ adb shell "cat /d/tracing/trace_pipe" | grep FPS

Change-Id: Ia1f804cbc7e297a85591e6b0f293ca1014301b74