arm64: IRQ handling

This patch adds the support for IRQ handling. The actual interrupt
controller will be part of a separate patch (going into
drivers/irqchip/).

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Nicolas Pitre <nico@linaro.org>
Acked-by: Olof Johansson <olof@lixom.net>
Acked-by: Santosh Shilimkar <santosh.shilimkar@ti.com>

arch/arm64/include/asm/irq.h

@@ -0,0 +1,8 @@
+#ifndef __ASM_IRQ_H
+#define __ASM_IRQ_H
+
+#include <asm-generic/irq.h>
+
+extern void (*handle_arch_irq)(struct pt_regs *);
+
+#endif