cpumask: remove references to struct irqaction's mask field.

Impact: cleanup

It's unused, since about 1995.  So remove all initialization of it in
preparation for actually removing the field.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Thomas Gleixner <tglx@linutronix.de>

arch/h8300/kernel/timer/tpu.c

@@ -65,7 +65,6 @@ static struct irqaction tpu_irq = {
 	.name		= "tpu",
 	.handler	= timer_interrupt,
 	.flags		= IRQF_DISABLED | IRQF_TIMER,
-	.mask		= CPU_MASK_NONE,
 };
 
 const static int __initdata divide_rate[] = {