fc-duart28-conf: replace find and check-eeprom with single show command The original design with separate find and check-eeprom commands was driven by the assumption that we had to bump off the ftdi_sio driver in order to read the EEPROM, while a USB device tree check could be done non-invasively. However, now that we know that we can read the EEPROM non-invasively too, we can simplify the tool with a single show command.