iommu/amd: Introduce per PCI segment device table

Introduce per PCI segment device table. All IOMMUs within the segment
will share this device table. This will replace global device
table i.e. amd_iommu_dev_table.

Also introduce helper function to get the device table for the given IOMMU.

Co-developed-by: Vasant Hegde <vasant.hegde@amd.com>
Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Link: https://lore.kernel.org/r/20220706113825.25582-4-vasant.hegde@amd.com


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