ia64: Use the core irq stats function

Let the core do the irq_desc resolution.

No functional change.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: ia64 <linux-ia64@vger.kernel.org>
Link: http://lkml.kernel.org/r/20140223212738.099977064@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --cc arch/ia64/kernel/irq_ia64.c
Simple merge