Switch LVS to "performance" cpufreq governor

This makes a huge difference on lvs300x, probably because
cpufreq adjustment is relatively slow and/or doesn't react
well to non-userspace loads.  Only downside is increased
power draw, but (a) it's only a handful of machines and
(b) We already do this on our database machines as well.

Change-Id: Ia4f332c507c56b1388c49da9ed3ca20ef9a4170e
Merge "Switch LVS to "performance" cpufreq governor" into production