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>
diff --git a/arch/mips/sni/rm200.c b/arch/mips/sni/rm200.c
index 5310aa7..a695a08 100644
--- a/arch/mips/sni/rm200.c
+++ b/arch/mips/sni/rm200.c
@@ -359,7 +359,8 @@
  * IRQ2 is cascade interrupt to second interrupt controller
  */
 static struct irqaction sni_rm200_irq2 = {
-	no_action, 0, CPU_MASK_NONE, "cascade", NULL, NULL
+	.handler = no_action,
+	.name = "cascade",
 };
 
 static struct resource sni_rm200_pic1_resource = {