iommu/amd: Remove the unused device errata code

The device errata mechism is entirely unused, so remove it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20210402143312.372386-2-hch@lst.de


Signed-off-by: Joerg Roedel <jroedel@suse.de>