dma-mapping: fix the prototype of dma_unmap_single()

dma_unmap_single() takes the dma address, not virtual address.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
diff --git a/drivers/mmc/tmio-common.c b/drivers/mmc/tmio-common.c
index 092b740..5321388 100644
--- a/drivers/mmc/tmio-common.c
+++ b/drivers/mmc/tmio-common.c
@@ -353,7 +353,7 @@
 	if (poll_flag == TMIO_SD_DMA_INFO1_END_RD)
 		udelay(1);
 
-	dma_unmap_single(buf, len, dir);
+	dma_unmap_single(dma_addr, len, dir);
 
 	return ret;
 }