genirq: Add new functions to dummy chips

The compat functions go away when the core code is converted.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/irq/internals.h b/kernel/irq/internals.h
index a805a00..562fc7e 100644
--- a/kernel/irq/internals.h
+++ b/kernel/irq/internals.h
@@ -4,6 +4,8 @@
 
 extern int noirqdebug;
 
+#define irq_data_to_desc(data)	container_of(data, struct irq_desc, irq_data)
+
 /* Set default functions for irq_chip structures: */
 extern void irq_chip_set_defaults(struct irq_chip *chip);