swiotlb: remove SWIOTLB_MAP_ERROR

We can use DMA_MAPPING_ERROR instead, which already maps to the same
value.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Jesper Dangaard Brouer <brouer@redhat.com>
Tested-by: Jesper Dangaard Brouer <brouer@redhat.com>
Tested-by: Tony Luck <tony.luck@intel.com>

drivers/xen/swiotlb-xen.c

@@ -403,7 +403,7 @@ static dma_addr_t xen_swiotlb_map_page(struct device *dev, struct page *page,
 
 	map = swiotlb_tbl_map_single(dev, start_dma_addr, phys, size, dir,
 				     attrs);
-	if (map == SWIOTLB_MAP_ERROR)
+	if (map == DMA_MAPPING_ERROR)
 		return DMA_MAPPING_ERROR;
 
 	dev_addr = xen_phys_to_bus(map);
@@ -572,7 +572,7 @@ xen_swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
 								 sg_phys(sg),
 								 sg->length,
 								 dir, attrs);
-			if (map == SWIOTLB_MAP_ERROR) {
+			if (map == DMA_MAPPING_ERROR) {
 				dev_warn(hwdev, "swiotlb buffer is full\n");
 				/* Don't panic here, we expect map_sg users
 				   to do proper error handling. */