On Chrome OS 3.14 we use the (downstream) interactive governor.  On
Chrome OS 4.19 we are planning to use the schedutil governor.  We'll
use USE flags to tell which one we're building for.

NOTE: the 'init.cpusets.rc' and 'platform-cpusets.conf' files were
copied from other people using the schedutil governor, but since we're
symmetric (all 4 processors are A17) I killed some parts of it, just
keeping the schedtune stuff.

BUG=chromium:950960
TEST=Set USE flags, emerge, and cros deploy; look at sysfs files
Cq-Depend: chromium:1595334

Change-Id: I44f5db58bf4022ad8bc5d1df6173944843e8cb73
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/1597953


Commit-Ready: ChromeOS CL Exonerator Bot <chromiumos-cl-exonerator@appspot.gserviceaccount.com>
Reviewed-by: Sonny Rao <sonnyrao@chromium.org>