arm64: Use irqchip_init() for interrupt controller initialisation

This patch uses the generic irqchip_init() function for initialising the
interrupt controller on arm64. It also adds several definitions required
by the ARM GIC irqchip driver but does not enable ARM_GIC yet.

Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
diff --git a/arch/arm64/include/asm/exception.h b/arch/arm64/include/asm/exception.h
index ac63519..0303705 100644
--- a/arch/arm64/include/asm/exception.h
+++ b/arch/arm64/include/asm/exception.h
@@ -19,5 +19,6 @@
 #define __ASM_EXCEPTION_H
 
 #define __exception	__attribute__((section(".exception.text")))
+#define __exception_irq_entry	__exception
 
 #endif	/* __ASM_EXCEPTION_H */