If led count > 21 leds over 21 are not reset

[aleksas]

Following line is references hardcoded value relating to 21 leds. If more leds are operated leds over 21 are not reset. Should be value dependant on led count. https://github.com/hepingood/ws2812b/blob/84adf5dba5e46c66c2113dd92d5f45167b42b090/src/driver_ws2812b.c#L206

[libdriver]

Thank you very much for your suggestion. We have fixed the issue and you can pull it again.