iommu/amd: Test for PAGING domains before freeing a domain

This domain free function can be called for IDENTITY and SVA domains too,
and they don't have page tables. For now protect against this by checking
the type. Eventually the different types should have their own free
functions.

Fixes: 485534bf ("iommu/amd: Remove conditions from domain free paths")
Reported-by: Vasant Hegde <vasant.hegde@amd.com>
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Vasant Hegde <vasant.hegde@amd.com>
Link: https://lore.kernel.org/r/0-v1-ad9884ee5f5b+da-amd_iopgtbl_fix_jgg@nvidia.com


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