pegasos2: rom reconstruction

@kas1e
I probably did not have to implement anything for this so it's handled by QEMU in some way that I don't know. If the VT8231 has some bits to disable PS2 ports those are likely not emulated but if you add -device usb-kbd then QEMU will direct keyboard input to that so it should work with USB as well. I don't know if the default PS2 keyboard also gets keyboard input with -device usb-kbd but could be that both keep working. Maybe on real machine also both should work but SmartFirmware has only one input source so you can either use PS2 or USB keyboard? In any case you can test with original firmware with -device usb-kbd and if that works with your version too then maybe it's OK.