Added vendor string for Open DMX clone from KWMATIK

Recently I bought an inexpensive Open DMX clone from KWMATIK, a polish manufacturer, via ebay.

This is the product page for reference: http://www.kwmatik.cba.pl/en/edmx.html

I wanted to use it together with OLA to control some RGB lights. The FTDI driver did not seem to recognize the interface, so I checked the logs and found out that the vendor string is not whitelisted. After a small modification the interface was working flawlessly.