dmaengine: dw: select DW_DMAC_BIG_ENDIAN_IO automagically

Signed-off-by: Vinod Koul <vinod.koul@intel.com>
diff --git a/drivers/dma/dw/regs.h b/drivers/dma/dw/regs.h
index 07c5a6e..deb4274 100644
--- a/drivers/dma/dw/regs.h
+++ b/drivers/dma/dw/regs.h
@@ -101,6 +101,12 @@
 	u32	DW_PARAMS;
 };
 
+/*
+ * Big endian I/O access when reading and writing to the DMA controller
+ * registers.  This is needed on some platforms, like the Atmel AVR32
+ * architecture.
+ */
+
 #ifdef CONFIG_DW_DMAC_BIG_ENDIAN_IO
 #define dma_readl_native ioread32be
 #define dma_writel_native iowrite32be