DMA: of: Constant names

No DMA of-function alters the name, so this patch changes the name arguments
to be constant. Most drivers will probably request DMA channels using a
constant name.

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
Signed-off-by: Vinod Koul <vinod.koul@intel.com>
diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h
index 91ac8da..274071c 100644
--- a/include/linux/dmaengine.h
+++ b/include/linux/dmaengine.h
@@ -968,7 +968,7 @@
 enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx);
 void dma_issue_pending_all(void);
 struct dma_chan *__dma_request_channel(dma_cap_mask_t *mask, dma_filter_fn fn, void *fn_param);
-struct dma_chan *dma_request_slave_channel(struct device *dev, char *name);
+struct dma_chan *dma_request_slave_channel(struct device *dev, const char *name);
 void dma_release_channel(struct dma_chan *chan);
 #else
 static inline enum dma_status dma_wait_for_async_tx(struct dma_async_tx_descriptor *tx)
@@ -984,7 +984,7 @@
 	return NULL;
 }
 static inline struct dma_chan *dma_request_slave_channel(struct device *dev,
-							 char *name)
+							 const char *name)
 {
 	return NULL;
 }