Based on PegasusQ. Introducing cpu frequency limitations based on the number of cores online, stanby frequency and online cores limitations.

Fixed standby CPU freq. limit not being applied if current number of cores online <= to max_cpu_lock_stdby.
Fixed enforce CPU freq. limit at all times.
Removed limit of cores in standby, it's limited at one anyway.

sysfs interface :

- cpu_max_freq_1 : max. freq. applied when running on 1 core (defaults to 1.0GHz)
- cpu_max_freq_2 : max. freq. applied when running on 2 cores (defaults to 1.1GHz)
- cpu_max_freq_3 : max. freq. applied when running on 3 cores (defaults to 1.2GHz)
- cpu_max_freq_4 : max. freq. applied when running on 4 cores (defaults to 1.4GHz)
- cpu_max_freq_current : currently applied max. frequency (read-only)
- cpu_max_freq_stdby : max. freq. applied when screen off (defaults to 800MHz)

NB: hotplug frequencies and rq thresholds have been revised up to keep the device running on as little cores as possible.