swiotlb: use unmap_single instead of swiotlb_unmap_single in swiotlb_free_coherent

We don't need any check in swiotlb_unmap_single here. unmap_single is
appropriate.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/lib/swiotlb.c b/lib/swiotlb.c
index 2fb485d..bf61c73 100644
--- a/lib/swiotlb.c
+++ b/lib/swiotlb.c
@@ -513,7 +513,7 @@
 		free_pages((unsigned long) vaddr, get_order(size));
 	else
 		/* DMA_TO_DEVICE to avoid memcpy in unmap_single */
-		swiotlb_unmap_single (hwdev, dma_handle, size, DMA_TO_DEVICE);
+		unmap_single(hwdev, vaddr, size, DMA_TO_DEVICE);
 }
 
 static void