[ARM SMP] Add hotplug CPU infrastructure

This patch adds the infrastructure to support hotplug CPU on ARM
platforms.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/include/asm-arm/irq.h b/include/asm-arm/irq.h
index f97912f..59975ee 100644
--- a/include/asm-arm/irq.h
+++ b/include/asm-arm/irq.h
@@ -47,5 +47,6 @@
 struct pt_regs;
 int handle_IRQ_event(unsigned int, struct pt_regs *, struct irqaction *);
 
+extern void migrate_irqs(void);
 #endif