iommu/vt-d: Remove finding domain in dmar_insert_one_dev_info()

The Intel IOMMU driver has already converted to use default domain
framework in iommu core. There's no need to find a domain for the
device in the domain attaching path. Cleanup that code.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20220214025704.3184654-1-baolu.lu@linux.intel.com
Link: https://lore.kernel.org/r/20220301020159.633356-3-baolu.lu@linux.intel.com


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