x86: Don't setup ioapic irq for sci twice

The sparseirq rework triggered a warning in the iommu code, which was
caused by setting up ioapic for ACPI irq 9 twice. This function is
solely to handle interrupts which are on a secondary ioapic and
outside the legacy irq range.

Replace the sparse irq_to_desc check with a non ifdeffed version.

[ tglx: Moved it before the ioapic sparse conversion and simplified
  	the inverse logic ]

Signed-off-by: Yinghai Lu <yinghai@kernel.org>
LKML-Reference: <4CB00122.3030301@kernel.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/apic/io_apic.c

@@ -1565,11 +1565,11 @@ void setup_IO_APIC_irq_extra(u32 gsi)
 		return;
 
 	irq = pin_2_irq(idx, apic_id, pin);
-#ifdef CONFIG_SPARSE_IRQ
-	desc = irq_to_desc(irq);
-	if (desc)
+
+	/* Only handle the non legacy irqs on secondary ioapics */
+	if (apic_id == 0 || irq < NR_IRQS_LEGACY)
 		return;
-#endif
+
 	desc = irq_to_desc_alloc_node(irq, node);
 	if (!desc) {
 		printk(KERN_INFO "can not get irq_desc for %d\n", irq);