udmabuf: constify udmabuf_create args

Reported-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: NGerd Hoffmann <kraxel@redhat.com>
Reviewed-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Acked-by: NDaniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20180911134216.9760-6-kraxel@redhat.com

drivers/dma-buf/udmabuf.c

@@ -116,8 +116,8 @@ static const struct dma_buf_ops udmabuf_ops = {
 #define SEALS_WANTED (F_SEAL_SHRINK)
 #define SEALS_DENIED (F_SEAL_WRITE)
 
-static long udmabuf_create(struct udmabuf_create_list *head,
-			   struct udmabuf_create_item *list)
+static long udmabuf_create(const struct udmabuf_create_list *head,
+			   const struct udmabuf_create_item *list)
 {
 	DEFINE_DMA_BUF_EXPORT_INFO(exp_info);
 	struct file *memfd = NULL;