irq: update all arches for new irq_desc

Impact: cleanup, update to new cpumask API

Irq_desc.affinity and irq_desc.pending_mask are now cpumask_var_t's
so access to them should be using the new cpumask API.

Signed-off-by: Mike Travis <travis@sgi.com>
diff --git a/arch/mips/kernel/smtc.c b/arch/mips/kernel/smtc.c
index b6cca01..d2c1ab1 100644
--- a/arch/mips/kernel/smtc.c
+++ b/arch/mips/kernel/smtc.c
@@ -686,7 +686,7 @@
 	 * and efficiency, we just pick the easiest one to find.
 	 */
 
-	target = first_cpu(irq_desc[irq].affinity);
+	target = cpumask_first(irq_desc[irq].affinity);
 
 	/*
 	 * We depend on the platform code to have correctly processed