Mach64 drm driver disabled in -master

[Francois Tigeot]

Hi,

The Mach64 drm driver is used to accelerate OpenGL operations on
the ATI 3D Rage family of graphics card from the 1990s.

With some of the latest changes I made to make the DragonFly drm
graphic stack more similar to the Linux 3.8 one, it doesn't compile
anymore.
Unlike others, this driver was never integrated in the Linux
kernel and thus fixes have to be created locally.

I have disabled it for now; if someone has this kind of hardware,
I'd like to hear about it. Your help will be needed to ensure this
driver stays working in the future.

-- 
Francois Tigeot