genirq: Enhance irq_data_to_desc() to support hierarchy irqdomain

For irq associated with hierarchy irqdomains, there will be multiple
irq_datas for one irq_desc. So enhance irq_data_to_desc() to support
hierarchy irqdomain. Also export irq_data_to_desc() as an inline
function for later reuse.

Signed-off-by: Jiang Liu <jiang.liu@linux.intel.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Marc Zyngier <marc.zyngier@arm.com>
Link: http://lkml.kernel.org/r/1433145945-789-2-git-send-email-jiang.liu@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

kernel/irq/internals.h

@@ -59,8 +59,6 @@ enum {
 #include "debug.h"
 #include "settings.h"
 
-#define irq_data_to_desc(data)	container_of(data, struct irq_desc, irq_data)
-
 extern int __irq_set_trigger(struct irq_desc *desc, unsigned int irq,
 		unsigned long flags);
 extern void __disable_irq(struct irq_desc *desc, unsigned int irq);