iommu/vt-d: Change return type of dmar_insert_one_dev_info()

iommu/vt-d: Change return type of dmar_insert_one_dev_info()

The dmar_insert_one_dev_info() returns the pass-in domain on success and
NULL on failure. This doesn't make much sense. Change it to an integer.

Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20220416120423.879552-1-baolu.lu@linux.intel.com
Link: https://lore.kernel.org/r/20220510023407.2759143-3-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>