x86: ioapic: Add io_apic_setup_irq_pin()

There are about four places in the ioapic code which do exactly the
same setup sequence. Also the OF based ioapic setup needs that
function to avoid putting the OF specific code into ioapic.c

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/arch/x86/kernel/apic/io_apic.c b/arch/x86/kernel/apic/io_apic.c
index f751a82..6deb3ca 100644
--- a/arch/x86/kernel/apic/io_apic.c
+++ b/arch/x86/kernel/apic/io_apic.c
@@ -3607,6 +3607,21 @@
 }
 #endif /* CONFIG_HT_IRQ */
 
+int
+io_apic_setup_irq_pin(unsigned int irq, int node, struct io_apic_irq_attr *attr)
+{
+	struct irq_cfg *cfg = alloc_irq_and_cfg_at(irq, node);
+	int ret;
+
+	if (!cfg)
+		return -EINVAL;
+	ret = __add_pin_to_irq_node(cfg, node, attr->ioapic, attr->ioapic_pin);
+	if (!ret)
+		setup_ioapic_irq(attr->ioapic, attr->ioapic_pin, irq, cfg,
+				 attr->trigger, attr->polarity);
+	return ret;
+}
+
 int __init io_apic_get_redir_entries (int ioapic)
 {
 	union IO_APIC_reg_01	reg_01;