x86: io_apic: Avoid unused variable warning when CONFIG_GENERIC_PENDING_IRQ=n

arch/x86/kernel/apic/io_apic.c: In function 'ack_apic_level':
arch/x86/kernel/apic/io_apic.c:2433: warning: unused variable 'desc'
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
LKML-Reference: <201010272107.o9RL7rse018212@imap1.linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

arch/x86/kernel/apic/io_apic.c

@@ -2430,13 +2430,12 @@ static void ack_apic_level(struct irq_data *data)
 {
 	struct irq_cfg *cfg = data->chip_data;
 	int i, do_unmask_irq = 0, irq = data->irq;
-	struct irq_desc *desc = irq_to_desc(irq);
 	unsigned long v;
 
 	irq_complete_move(cfg);
 #ifdef CONFIG_GENERIC_PENDING_IRQ
 	/* If we are moving the irq we need to mask it */
-	if (unlikely(desc->status & IRQ_MOVE_PENDING)) {
+	if (unlikely(irq_to_desc(irq)->status & IRQ_MOVE_PENDING)) {
 		do_unmask_irq = 1;
 		mask_ioapic(cfg);
 	}