0c3db448bb
added the option to generate the waveforms to drive ws2812 and similar LEDs using different
hardware (e.g. RP2040 PIO instead of SPI).
For that new mode, the concept of CONFIG_WS2812_FREQUENCY is different. Instead of
the SPI frequency (commonly a few MHz), it is the frequency of the actual output waveform
(commonly 400 or 800 kHz).
There was an attempt to express the SPI frequency divided by 10, but it's not actually the
case either (it would be divided by 8).
I think it is clearer to explain in Kconfig what CONFIG_WS2812_FREQUENCY means for each mode
and go back to the previous behaviour for the original SPI mode (also to avoid breaking
out-of-tree boards).
e1e89b925f