MIPS: JZ4740: Move arch_init_irq out of arch/mips/jz4740/irq.c

In preparation for moving the JZ4740 interrupt controller driver to
drivers/irqchip, move arch_init_irq into setup.c such that everything
remaining in irq.c is related to said JZ4740 interrupt controller.

Signed-off-by: Paul Burton <paul.burton@imgtec.com>
Cc: Lars-Peter Clausen <lars@metafoo.de>
Cc: linux-mips@linux-mips.org
Cc: linux-kernel@vger.kernel.org
Cc: Brian Norris <computersforpeace@gmail.com>
Patchwork: https://patchwork.linux-mips.org/patch/10136/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/jz4740/setup.c b/arch/mips/jz4740/setup.c
index d6bb7a3..4808730 100644
--- a/arch/mips/jz4740/setup.c
+++ b/arch/mips/jz4740/setup.c
@@ -16,6 +16,7 @@
 
 #include <linux/init.h>
 #include <linux/io.h>
+#include <linux/irqchip.h>
 #include <linux/kernel.h>
 #include <linux/of_fdt.h>
 #include <linux/of_platform.h>
@@ -24,6 +25,7 @@
 #include <asm/prom.h>
 
 #include <asm/mach-jz4740/base.h>
+#include <asm/mach-jz4740/irq.h>
 
 #include "reset.h"
 
@@ -78,3 +80,9 @@
 {
 	return "JZ4740";
 }
+
+void __init arch_init_irq(void)
+{
+	irqchip_init();
+	jz4740_intc_init();
+}