[PATCH v2] agp/amd64: Check AGP Capability before binding to unsupported devices

[Andi Kleen]

I suspect these days it would be also reasonable to drop it this old
hack.

If any of these old chipsets are still missing I would rather adds its
PCI-ID.

There will be certainly not any new unknown ones for these old CPUs.

Also there shouldn't be that many high speed devices that need the 
old 4GB IOMMU anyways, and for low speed ones it's fine to use swiotlb
instead.

-Andi