CH59x porting

[pwilkowski]

I was wondering how hard it would be to port this core (which i love for ESP32 and nrf52840) to risc-v CH592X (and possibly other mcus from WCH)

there is already a minimal HAL made for those MCUs https://github.com/cnlohr/ch32fun

which does include ISLER https://github.com/cnlohr/ch32fun/blob/master/extralibs/iSLER.h
Industry Standard Low Energy Radio (iSLER) RX/TX for ch32fun