iommu/amd: Move the nid to pdom_setup_pgtable()

iommu/amd: Move the nid to pdom_setup_pgtable()

The only thing that uses the nid is the io_pgtable code, and it should be
set before calling alloc_io_pgtable_ops() to ensure that the top levels
are allocated on the correct nid.

Since dev is never NULL now we can just do this trivially and remove the
other uses of nid. SVA and identity code paths never use it since they
don't use io_pgtable.

Reviewed-by: Vasant Hegde <vasant.hegde@amd.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/6-v2-9776c53c2966+1c7-amd_paging_flags_jgg@nvidia.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>