firewire: fw-sbp2: prepare for s/g chaining

Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>

drivers/firewire/fw-sbp2.c

@@ -1107,9 +1107,9 @@ sbp2_map_scatterlist(struct sbp2_command_orb *orb, struct fw_device *device,
 	 * elements larger than 65535 bytes, some IOMMUs may merge sg elements
 	 * during DMA mapping, and Linux currently doesn't prevent this.
 	 */
-	for (i = 0, j = 0; i < count; i++) {
-		sg_len = sg_dma_len(sg + i);
-		sg_addr = sg_dma_address(sg + i);
+	for (i = 0, j = 0; i < count; i++, sg = sg_next(sg)) {
+		sg_len = sg_dma_len(sg);
+		sg_addr = sg_dma_address(sg);
 		while (sg_len) {
 			/* FIXME: This won't get us out of the pinch. */
 			if (unlikely(j >= ARRAY_SIZE(orb->page_table))) {