eepmake: eep file generate with wrong informations (multiple custom file)

[Majonsi]

When an eep file is generate with multiple custom file the generated eep file contain wrong information. The UUID is not the one set in the eeprom_settings.txt thats the same story with the VendorId and the ProductId.
After several test I found that the UUID change a little bit with 2 customs files and the UUID change a lot with 3 custom files.

[nucatus]

I can confirm this behavior myself. If multiple custom fields are provided, no matter they are provided as input files using the -c flag, or statically, in the eeprom_settings.txt file, the UUID field defined in the eeprom_settings.txt file is altered in a weird way.