of/irq: remove references to NO_IRQ in drivers/of/platform.c

Instead of referencing NO_IRQ in platform.c, define some helper functions
in irq.c to call instead from platform.c.  Keep NO_IRQ usage local to
irq.c, and define NO_IRQ if not defined in headers.

Signed-off-by: Andres Salomon <dilinger@queued.net>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
diff --git a/include/linux/of_irq.h b/include/linux/of_irq.h
index 5929781..090cbaa 100644
--- a/include/linux/of_irq.h
+++ b/include/linux/of_irq.h
@@ -64,6 +64,9 @@
 					  unsigned int intsize);
 extern int of_irq_to_resource(struct device_node *dev, int index,
 			      struct resource *r);
+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);
 
 #endif /* CONFIG_OF_IRQ */
 #endif /* CONFIG_OF */