iommu/amd: Fix possible memory leak of 'domain'

Move allocation code down to avoid memory leak.

Fixes: 29f54745 ("iommu/amd: Add missing domain type checks")
Signed-off-by: Su Hui <suhui@nfschina.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Jerry Snitselaar <jsnitsel@redhat.com>
Reviewed-by: Vasant Hegde <vasant.hegde@amd.com>
Link: https://lore.kernel.org/r/20230608021933.856045-1-suhui@nfschina.com


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