[IA64] Fix kstat_this_cpu build breakage

[IA64] Fix kstat_this_cpu build breakage

arch/ia64/kernel/irq_ia64.c: In function 'ia64_handle_irq':
arch/ia64/kernel/irq_ia64.c:498: error: 'struct kernel_stat' has no member named 'irqs'
arch/ia64/kernel/irq_ia64.c:500: error: 'struct kernel_stat' has no member named 'irqs'
arch/ia64/kernel/irq_ia64.c: In function 'ia64_process_pending_intr':
arch/ia64/kernel/irq_ia64.c:556: error: 'struct kernel_stat' has no member named 'irqs'
arch/ia64/kernel/irq_ia64.c:558: error: 'struct kernel_stat' has no member named 'irqs'

Fix build breakage due to recent kstat_this_cpu changes in:
   d7e51e66899f95dabc89b4d4c6674a6e50fa37fc
   sparseirq: make some func to be used with genirq

Signed-off-by: Jes Sorensen <jes@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>