dma-buf: Constify ops argument to dma_buf_export()

This allows drivers to make the dma buf operations structure constant.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
index f8ac076..86f6241 100644
--- a/include/linux/dma-buf.h
+++ b/include/linux/dma-buf.h
@@ -114,8 +114,8 @@
 							struct device *dev);
 void dma_buf_detach(struct dma_buf *dmabuf,
 				struct dma_buf_attachment *dmabuf_attach);
-struct dma_buf *dma_buf_export(void *priv, struct dma_buf_ops *ops,
-			size_t size, int flags);
+struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops,
+			       size_t size, int flags);
 int dma_buf_fd(struct dma_buf *dmabuf);
 struct dma_buf *dma_buf_get(int fd);
 void dma_buf_put(struct dma_buf *dmabuf);
@@ -138,8 +138,8 @@
 }
 
 static inline struct dma_buf *dma_buf_export(void *priv,
-						struct dma_buf_ops *ops,
-						size_t size, int flags)
+					     const struct dma_buf_ops *ops,
+					     size_t size, int flags)
 {
 	return ERR_PTR(-ENODEV);
 }