cpufreq: interactive: change the calculation of the target frequency
Thanks @ franciscofranco.
cpufreq: interactive: calculate the load based on max (which is volatile) and not cpuinfo.max_freq, which is always 3GHz.

Signed-off-by: franciscofranco <franciscofranco.1990@gmail.com>
cpufreq: interactive: remove unused code
cpufreq: interactive: decrease timer_slack to 70ms

4 * timer_rate could lead to enourmous defferable timer and sometimes,
even during screen off we might need cpufreq to react fast so lowered
timer_slack will help with that. This is specific to interactive, other
governors handle their routines differently.