Missing critical phys_to_virt in lib/swiotlb.c

Adds missing call to phys_to_virt() in the
lib/swiotlb.c:swiotlb_sync_sg() function.  Without this change, a kernel
panic will always occur whenever a SWIOTLB bounce buffer from a
scatter-gather list gets synced.
Signed-off-by: David Moore <dcm@acm.org>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

lib/swiotlb.c

@@ -750,7 +750,7 @@ swiotlb_sync_sg(struct device *hwdev, struct scatterlist *sg,
 
 	for (i = 0; i < nelems; i++, sg++)
 		if (sg->dma_address != SG_ENT_PHYS_ADDRESS(sg))
-			sync_single(hwdev, (void *) sg->dma_address,
+			sync_single(hwdev, phys_to_virt(sg->dma_address),
 				    sg->dma_length, dir, target);
 }