iommu/amd: Consolidate logic to allocate protection domain

iommu/amd: Consolidate logic to allocate protection domain

Move the logic into the common caller function to simplify the code.

No functional changes intended.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Link: https://lore.kernel.org/r/20230921092147.5930-4-vasant.hegde@amd.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>