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/mtd/nand/raw/denali.c b/drivers/mtd/nand/raw/denali.c
index f51d3e2..3e0ac39 100644
--- a/drivers/mtd/nand/raw/denali.c
+++ b/drivers/mtd/nand/raw/denali.c
@@ -581,7 +581,7 @@
 
 	iowrite32(0, denali->reg + DMA_ENABLE);
 
-	dma_unmap_single(buf, size, dir);
+	dma_unmap_single(dma_addr, size, dir);
 
 	if (irq_status & INTR__ERASED_PAGE)
 		memset(buf, 0xff, size);