[FEATURE] 20/7/6 Mhz Z80 turbo mode

[GuerreroNinja]

Panasonic Panasonic A1-WSX and FS-A1WX MSX2+ models includes a faster Z80 CPU that can run at 6Mhz (turbo mode). Some MSX2 hacks allows to install a 7Mhz Z80 CPU with an ON/OFF switch. Some people have succesfully installed a 20Mhz Z80:

https://hackaday.io/project/175574-msx-compatible-boards-for-rc2014/log/203333-turbo-cpu

The turbo mode has some problems though, as a lot of software won't run properly due to the lost sync with memory, VDP...

However, if this implementation is simple enough, it can open some possibilities like future MSX2+ Panasonic implementation or running some programs faster.

I don't know if this is feasible or difficult, please feel free to close it. Thank you for your GREAT work Tomas!!