iommu/amd: Miscellaneous clean up when free domain

* Use the protection_domain_free() helper function to free domain.
  The function has been modified to also free memory used for the v1 and v2
  page tables. Also clear gcr3 table in v2 page table free path.

* Refactor code into cleanup_domain() for reusability. Change BUG_ON to
  WARN_ON in cleanup path.

* Protection domain dev_cnt should be read when the domain is locked.

Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
Co-developed-by: Vasant Hegde <vasant.hegde@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/20230921092147.5930-8-vasant.hegde@amd.com


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