iommu/amd: Free domain ID after domain_flush_pages

free_io_pgtable_ops() path uses domain ID to flush pages. Hence
free domain ID after flushing everything.

Signed-off-by: Vasant Hegde <vasant.hegde@amd.com>
Link: https://lore.kernel.org/r/20220912063248.7909-4-vasant.hegde@amd.com


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