backends/iommufd: iommufd_backend_map_file_dma

backends/iommufd: iommufd_backend_map_file_dma

Define iommufd_backend_map_file_dma to implement IOMMU_IOAS_MAP_FILE.
This will be called as a substitute for iommufd_backend_map_dma, so
the error conditions for BARs are copied as-is from that function.

Signed-off-by: Steve Sistare <steven.sistare@oracle.com>
Reviewed-by: Zhenzhong Duan <zhenzhong.duan@intel.com>
Link: https://lore.kernel.org/qemu-devel/1751493538-202042-6-git-send-email-steven.sistare@oracle.com
Signed-off-by: Cédric Le Goater <clg@redhat.com>