[PATCH] x86_64: Use the e820 hole to map the IOMMU/AGP aperture

This might save memory on some Opteron systems without AGP bridge.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>