ia64: Remove unused check_irq_used()

Just stumbled over it when staring into ia64 irq handling.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Grant Likely <grant.likely@linaro.org>
Tested-by: Tony Luck <tony.luck@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Link: http://lkml.kernel.org/r/20140507154336.566531793@linutronix.deSigned-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/ia64/include/asm/hw_irq.h

@@ -132,7 +132,6 @@ extern int reserve_irq_vector (int vector);
 extern void __setup_vector_irq(int cpu);
 extern void ia64_send_ipi (int cpu, int vector, int delivery_mode, int redirect);
 extern void ia64_native_register_percpu_irq (ia64_vector vec, struct irqaction *action);
-extern int check_irq_used (int irq);
 extern void destroy_and_reserve_irq (unsigned int irq);
 
 #if defined(CONFIG_SMP) && (defined(CONFIG_IA64_GENERIC) || defined(CONFIG_IA64_DIG))

arch/ia64/kernel/irq_ia64.c

@@ -93,14 +93,6 @@ static int irq_status[NR_IRQS] = {
 	[0 ... NR_IRQS -1] = IRQ_UNUSED
 };
 
-int check_irq_used(int irq)
-{
-	if (irq_status[irq] == IRQ_USED)
-		return 1;
-
-	return -1;
-}
-
 static inline int find_unassigned_irq(void)
 {
 	int irq;