IRQ: Typedef the IRQ handler function type

Typedef the IRQ handler function type.

Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 1356d1e5fd256997e3d3dce0777ab787d0515c7a commit)
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 1f97e3d..1978235 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -64,8 +64,10 @@
 #define SA_TRIGGER_RISING	IRQF_TRIGGER_RISING
 #define SA_TRIGGER_MASK		IRQF_TRIGGER_MASK
 
+typedef irqreturn_t (*irq_handler_t)(int, void *, struct pt_regs *);
+
 struct irqaction {
-	irqreturn_t (*handler)(int, void *, struct pt_regs *);
+	irq_handler_t handler;
 	unsigned long flags;
 	cpumask_t mask;
 	const char *name;
@@ -76,8 +78,7 @@
 };
 
 extern irqreturn_t no_action(int cpl, void *dev_id, struct pt_regs *regs);
-extern int request_irq(unsigned int,
-		       irqreturn_t (*handler)(int, void *, struct pt_regs *),
+extern int request_irq(unsigned int, irq_handler_t handler,
 		       unsigned long, const char *, void *);
 extern void free_irq(unsigned int, void *);