iommu/vt-d: Use pci_get_domain_bus_and_slot() in pgtable_walk()

Use pci_get_domain_bus_and_slot() instead of searching the global list
to retrieve the pci device pointer. This also removes the global
device_domain_list as there isn't any consumer anymore.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Link: https://lore.kernel.org/r/20220706025524.2904370-4-baolu.lu@linux.intel.com


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