Remove the calgary iommu driver

From: Christoph Hellwig
Date: Wed Nov 13 2019 - 02:18:47 EST


Hi all,

per the discussion a few month ago with Jon we've agreed that the
calgary iommu driver is obsolete and in the way. Jon said back then
he'd send a patch to remove it, but as that didn't happen I prepared
one, plus two small cleanups touching the same area.