cpufreq: interactive: fix overclocking with high values

hispeed_freq would prevent interactive to scale above
600Mhz.
Fixing this by setting a higher value.

Signed-off-by: Blechd0se <alex.christ@hotmail.de>
cpufreq: interactive: squash in all commits

From over here; https://github.com/Blechd0se/kernel-moto-g/blob/4591cd1fd1be40fc454dfa38c1f60d20d9b24de8/drivers/cpufreq/cpufreq_interactive.c
Should prevent scaling up/down when near zero load and
removed the idle_notifier.

Signed-off-by: Blechd0se <alex.christ@hotmail.de>