[ARM] 5360/1: Orion: fix compilation error

Commit ba84be2338 broke the build.

Signed-off-by: Nicolas Pitre <nico@marvell.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

arch/arm/mach-orion5x/pci.c

@@ -13,6 +13,7 @@
 #include <linux/kernel.h>
 #include <linux/pci.h>
 #include <linux/mbus.h>
+#include <asm/irq.h>
 #include <asm/mach/pci.h>
 #include <plat/pcie.h>
 #include "common.h"