[Nouveau] wfb patches

[Maarten Maathuis]

These patches are pretty much done, except for a compile warning somewhere.

The major remaining bottleneck is this line (as far as i can tell):

offset -= (unsigned long) pPixmap->devPrivate.ptr;

A significant amount of samples is spent on that, so suggestions on
how to improve that are appreciated.

I'm out of time for the moment.

I'm curious how this performs for other people (obviously with Option
"EXAPixmaps" "1").

You will need a git'ish xserver for this to work and ofcource a geforce8 or 9.

Maarten.