add map/unmap_single_attr and map/unmap_sg_attr to struct dma_mapping_ops
This adds map/unmap_single_attr and map/unmap_sg_attr to struct
dma_mapping_ops. This enables us to move the dma operations in struct
ia64_machine_vector to struct dma_mapping_ops.
Note that we will remove map/unmap_sg and map/umap_single.
This is a preparation of struct dma_mapping_ops unification.