Re-generating the SoC/Software headers was causing some un-expected behaviours for users not familiar
with the flow. For example doing a --load with a different configuration, was re-generating the Software
headers and messing up things when trying to run software on the SoC.
Moving CRG simplify reset with NaxRiscv debug module and is in fact more logical.
Also do some minor updates/cosmetic changes while touching CRG/SoCCore.
rst was not directly assigned/used on reset_less clock domains, so reset_less
property was not really useful. With the changes on stream.CDC, having a rst
(Even fixed at 0) is now mandatory on clock domains involved in the CDC, so this
also fixes targets.
CPU parameters are now selectively exposed to the user:
./digilent_arty.py --cpu-type=vexriscv_smp --help will show VexRiscv-SMP parameters.
./digilent_arty.py --cpu-type=naxriscv --help will show NaxRiscv parameters.
