Set iInterface=serprog

[Rigo-V]

For compatibility with an udev rules like:

DRIVERS=="cdc_acm", ATTRS{interface}=="serprog", SYMLINK+="serprog%n"

With an stm32-vserprog and a pico-serprog board plugged in, I automatically get: /dev/serprog0 (->/dev/ttyACM0) /dev/serprog1 (->/dev/ttyACM1)