of: Export of_irq_find_parent()

We have platform code that needs to find a node's interrupt parent, so
export of_irq_find_parent() so we can use it.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

drivers/of/irq.c

@@ -56,7 +56,7 @@ EXPORT_SYMBOL_GPL(irq_of_parse_and_map);
  * Returns a pointer to the interrupt parent node, or NULL if the interrupt
  * parent could not be determined.
  */
-static struct device_node *of_irq_find_parent(struct device_node *child)
+struct device_node *of_irq_find_parent(struct device_node *child)
 {
 	struct device_node *p;
 	const __be32 *parp;

include/linux/of_irq.h

@@ -68,6 +68,7 @@ extern int of_irq_to_resource(struct device_node *dev, int index,
 extern int of_irq_count(struct device_node *dev);
 extern int of_irq_to_resource_table(struct device_node *dev,
 		struct resource *res, int nr_irqs);
+extern struct device_node *of_irq_find_parent(struct device_node *child);
 
 #endif /* CONFIG_OF_IRQ */
 #endif /* CONFIG_OF */