Specific integrated ROM/SRAM/MAIN_RAM size can be passed through command line parameters.
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.