genirq: use iterators for irq_desc loops

Use for_each_irq_desc[_reverse] for all the iteration loops.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index a69368f..c815b42 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -268,9 +268,10 @@
 
 void early_init_irq_lock_class(void)
 {
+	struct irq_desc *desc;
 	int i;
 
-	for (i = 0; i < nr_irqs; i++)
-		lockdep_set_class(&irq_desc[i].lock, &irq_desc_lock_class);
+	for_each_irq_desc(i, desc)
+		lockdep_set_class(&desc->lock, &irq_desc_lock_class);
 }
 #endif