iommu/amd: Use protection_domain.flags to check page table mode

iommu/amd: Use protection_domain.flags to check page table mode

Page table mode (v1, v2 or pt) is per domain property. Recently we have
enhanced protection_domain.pd_mode to track per domain page table mode.
Use that variable to check the page table mode instead of global
'amd_iommu_pgtable' in {map/unmap}_pages path.

Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/20240205115615.6053-7-vasant.hegde@amd.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>