genirq: Sanitize irq_data accessors

Get the data structure from the core and provide inline wrappers to
access the irq_data members.

Provide accessor inlines for irq_data as well.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@elte.hu>

kernel/irq/chip.c

@@ -256,6 +256,14 @@ int set_irq_chip_data(unsigned int irq, void *data)
 }
 EXPORT_SYMBOL(set_irq_chip_data);
 
+struct irq_data *irq_get_irq_data(unsigned int irq)
+{
+	struct irq_desc *desc = irq_to_desc(irq);
+
+	return desc ? &desc->irq_data : NULL;
+}
+EXPORT_SYMBOL_GPL(irq_get_irq_data);
+
 /**
  *	set_irq_nested_thread - Set/Reset the IRQ_NESTED_THREAD flag of an irq
  *