I solved the problem. It turned out the kernel did not have the ID for my chipset (Via 82C694X - Apollo Pro 133A). Since the kernel supports Apollo Pro and 694X just adds the 133MHz Bus afaik I assumed it would be safe to add the ID.
Now I have perfect OpenGL in FreeBSD =D. (I have posted this to the freebsd-stable mailinglist hoping that it will go into CURRENT and eventually into STABLE).