of: *node argument to of_parse_phandle_with_args should be const

The "struct device_node *" argument of of_parse_phandle_with_args() can
be const. Making this change makes it explicit that the function will
not modify a node.
Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
[grant.likely: Resolved conflict with previous patch modifying of_parse_phandle()]
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

drivers/of/base.c

@@ -1025,7 +1025,7 @@ EXPORT_SYMBOL(of_parse_phandle);
  * To get a device_node of the `node2' node you may call this:
  * of_parse_phandle_with_args(node3, "list", "#list-cells", 1, &args);
  */
-int of_parse_phandle_with_args(struct device_node *np, const char *list_name,
+int of_parse_phandle_with_args(const struct device_node *np, const char *list_name,
 				const char *cells_name, int index,
 				struct of_phandle_args *out_args)
 {

include/linux/of.h

@@ -273,7 +273,7 @@ extern int of_modalias_node(struct device_node *node, char *modalias, int len);
 extern struct device_node *of_parse_phandle(const struct device_node *np,
 					    const char *phandle_name,
 					    int index);
-extern int of_parse_phandle_with_args(struct device_node *np,
+extern int of_parse_phandle_with_args(const struct device_node *np,
 	const char *list_name, const char *cells_name, int index,
 	struct of_phandle_args *out_args);