DMA: shdma: make a pointer const

Platform data shouldn't be changed at run-time, so, pointers to it should
be const.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski+renesas@gmail.com>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
diff --git a/drivers/dma/sh/shdma.h b/drivers/dma/sh/shdma.h
index 06aae6e..3d9dca1 100644
--- a/drivers/dma/sh/shdma.h
+++ b/drivers/dma/sh/shdma.h
@@ -36,7 +36,7 @@
 struct sh_dmae_device {
 	struct shdma_dev shdma_dev;
 	struct sh_dmae_chan *chan[SH_DMAE_MAX_CHANNELS];
-	struct sh_dmae_pdata *pdata;
+	const struct sh_dmae_pdata *pdata;
 	struct list_head node;
 	void __iomem *chan_reg;
 	void __iomem *dmars;