ACPI: scan: Fix DMA range assignment

Assigning the device's dma_range_map from the iterator variable after
the loop means it always points to the empty terminator at the end of
the map, which is not what we want. Similarly, freeing the iterator on
error when it points to somwhere in the middle of the allocated array
won't work either. Fix this.

Fixes: bf2ee8d ("ACPI: scan: Support multiple DMA windows with different offsets")
Signed-off-by: Robin Murphy <robin.murphy@arm.com>
Reviewed-by: Jianmin Lv <lvjianmin@loongson.cn>
Tested-by: Jeremy Linton <jeremy.linton@arm.com>
Tested-by: Yicong Yang <yangyicong@hisilicon.com>
Reviewed-by: Lorenzo Pieralisi <lpieralisi@kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/acpi/scan.c

@@ -1509,9 +1509,12 @@ int acpi_dma_get_range(struct device *dev, const struct bus_dma_region **map)
 			goto out;
 		}
 
+		*map = r;
+
 		list_for_each_entry(rentry, &list, node) {
 			if (rentry->res->start >= rentry->res->end) {
-				kfree(r);
+				kfree(*map);
+				*map = NULL;
 				ret = -EINVAL;
 				dev_dbg(dma_dev, "Invalid DMA regions configuration\n");
 				goto out;
@@ -1523,8 +1526,6 @@ int acpi_dma_get_range(struct device *dev, const struct bus_dma_region **map)
 			r->offset = rentry->offset;
 			r++;
 		}
-
-		*map = r;
 	}
  out:
 	acpi_dev_free_resource_list(&list);