genirq: Add desc->irq_data accessor

We have accessors for all fields in irq_data based on irq_desc, but
not for irq_data itself.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/include/linux/irqdesc.h b/include/linux/irqdesc.h
index 9eb9cd31..0021837 100644
--- a/include/linux/irqdesc.h
+++ b/include/linux/irqdesc.h
@@ -109,6 +109,11 @@
 
 #ifdef CONFIG_GENERIC_HARDIRQS
 
+static inline struct irq_data *irq_desc_get_irq_data(struct irq_desc *desc)
+{
+	return &desc->irq_data;
+}
+
 static inline struct irq_chip *irq_desc_get_chip(struct irq_desc *desc)
 {
 	return desc->irq_data.chip;