Investigate /sys/class/pwm Support

[Kaiede]

Because of how locked down memory is outside of Raspbian, one thing that can be done to improve this is to enable use of the dtoverlay functionality that exposes the hardware PWM under /sys/class/pwm.

This might hamper performance a little with the overhead of interacting with the overlay instead of direct access, but should be investigated as a way to avoid having to access /dev/mem which is generally a no-no.