drivers/of: Return allocated memory from of_fdt_unflatten_tree()

This returns the allocate memory chunk, storing the unflattened device
tree, from of_fdt_unflatten_tree() so that memory chunk can be released
on demand in PowerNV PCI hotplug driver.

Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Rob Herring <robh@kernel.org>
diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
index 1bffcbd..901ec01 100644
--- a/include/linux/of_fdt.h
+++ b/include/linux/of_fdt.h
@@ -37,9 +37,9 @@
 				 unsigned long node);
 extern int of_fdt_match(const void *blob, unsigned long node,
 			const char *const *compat);
-extern void of_fdt_unflatten_tree(const unsigned long *blob,
-			       struct device_node *dad,
-			       struct device_node **mynodes);
+extern void *of_fdt_unflatten_tree(const unsigned long *blob,
+				   struct device_node *dad,
+				   struct device_node **mynodes);
 
 /* TBD: Temporary export of fdt globals - remove when code fully merged */
 extern int __initdata dt_root_addr_cells;