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/mips/kernel/cevt-sb1250.c

@@ -143,7 +143,6 @@ void __cpuinit sb1250_clockevent_init(void)
 
 	action->handler	= sibyte_counter_handler;
 	action->flags	= IRQF_DISABLED | IRQF_PERCPU;
-	action->mask	= cpumask_of_cpu(cpu);
 	action->name	= name;
 	action->dev_id	= cd;