iommu: Make set_dev_pasid op support domain replacement

The iommu core is going to support domain replacement for pasid, it needs
to make the set_dev_pasid op support replacing domain and keep the old
domain config in the failure case.

AMD iommu driver does not support domain replacement for pasid yet, so it
would fail the set_dev_pasid op to keep the old config if the input @old
is non-NULL. Till now, all the set_dev_pasid callbacks can handle the old
parameter and can keep the old config when failed, so update the kdoc of
set_dev_pasid op.

Suggested-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Kevin Tian <kevin.tian@intel.com>
Reviewed-by: Vasant Hegde <vasant.hegde@amd.com>
Signed-off-by: Yi Liu <yi.l.liu@intel.com>
Link: https://lore.kernel.org/r/20241107122234.7424-14-yi.l.liu@intel.com


Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>