drivers/of: Constify device_node->name and ->path_component_name

Neither of these should ever be changed once set. Make them const and
fix up the users that try to modify it in-place. In one case
kmalloc+memcpy is replaced with kstrdup() to avoid modifying the string.

Build tested with defconfigs on ARM, PowerPC, Sparc, MIPS, x86 among
others.

Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Julian Calaby <julian.calaby@gmail.com>
diff --git a/include/linux/of.h b/include/linux/of.h
index b4e50d5..857dde9 100644
--- a/include/linux/of.h
+++ b/include/linux/of.h
@@ -46,7 +46,7 @@
 	const char *name;
 	const char *type;
 	phandle phandle;
-	char	*full_name;
+	const char *full_name;
 
 	struct	property *properties;
 	struct	property *deadprops;	/* removed properties */
@@ -60,7 +60,7 @@
 	unsigned long _flags;
 	void	*data;
 #if defined(CONFIG_SPARC)
-	char	*path_component_name;
+	const char *path_component_name;
 	unsigned int unique_id;
 	struct of_irq_controller *irq_trans;
 #endif