Allow gcc to generate better code for irq handling.

Ok, now that most drivers have been converted to the new
irqreturn_t, we can remove the fascist type-checks and just
use a regular integer type which has a simpler calling
convention.

arch/i386/kernel/irq.c

@@ -213,7 +213,7 @@ int handle_IRQ_event(unsigned int irq, struct pt_regs * regs, struct irqaction *
 
 	do {
 		status |= action->flags;
-		retval |= action->handler(irq, action->dev_id, regs).val;
+		retval |= action->handler(irq, action->dev_id, regs);
 		action = action->next;
 	} while (action);
 	if (status & SA_SAMPLE_RANDOM)

include/linux/interrupt.h

@@ -25,13 +25,11 @@
  * IRQ_HANDLED means that we did have a valid interrupt and handled it.
  * IRQ_RETVAL(x) selects on the two depending on x being non-zero (for handled)
  */
-typedef struct irqreturn {
-	unsigned int val;
-} irqreturn_t;
+typedef int irqreturn_t;
 
-#define IRQ_NONE	((struct irqreturn) { 0 })
-#define IRQ_HANDLED	((struct irqreturn) { 1 })
-#define IRQ_RETVAL(x)	((struct irqreturn) { (x) != 0 })
+#define IRQ_NONE	(0)
+#define IRQ_HANDLED	(1)
+#define IRQ_RETVAL(x)	((x) != 0)
 
 struct irqaction {
 	irqreturn_t (*handler)(int, void *, struct pt_regs *);