[ARM] Ensure linux/hardirqs.h is included where required

... for the removal of it from asm-generic/local.h

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/mm/fault.c b/arch/arm/mm/fault.c
index 2df8d9f..22c9530 100644
--- a/arch/arm/mm/fault.c
+++ b/arch/arm/mm/fault.c
@@ -11,6 +11,7 @@
 #include <linux/module.h>
 #include <linux/signal.h>
 #include <linux/mm.h>
+#include <linux/hardirq.h>
 #include <linux/init.h>
 #include <linux/kprobes.h>
 #include <linux/uaccess.h>