cpufreq: Drop schedfreq governor

We all should be using (and improving) the schedutil governor now. Get
rid of the non-upstream governor.

Tested on Hikey.

Change-Id: I2104558b03118b0a9c5f099c23c42cd9a6c2a963
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>