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/sgi-ip32/ip32-irq.c

@@ -115,14 +115,12 @@ extern irqreturn_t crime_cpuerr_intr(int irq, void *dev_id);
 struct irqaction memerr_irq = {
 	.handler = crime_memerr_intr,
 	.flags = IRQF_DISABLED,
-	.mask = CPU_MASK_NONE,
 	.name = "CRIME memory error",
 };
 
 struct irqaction cpuerr_irq = {
 	.handler = crime_cpuerr_intr,
 	.flags = IRQF_DISABLED,
-	.mask = CPU_MASK_NONE,
 	.name = "CRIME CPU error",
 };