irq: introduce nr_irqs

at this point nr_irqs is equal NR_IRQS

convert a few easy users from NR_IRQS to dynamic nr_irqs.

v2: according to Eric, we need to take care of arch without generic_hardirqs

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/irq/handle.c b/kernel/irq/handle.c
index f4c8a03..e9d022c 100644
--- a/kernel/irq/handle.c
+++ b/kernel/irq/handle.c
@@ -47,6 +47,7 @@
  *
  * Controller mappings for all interrupt sources:
  */
+int nr_irqs = NR_IRQS;
 struct irq_desc irq_desc[NR_IRQS] __cacheline_aligned_in_smp = {
 	[0 ... NR_IRQS-1] = {
 		.status = IRQ_DISABLED,
@@ -265,7 +266,7 @@
 {
 	int i;
 
-	for (i = 0; i < NR_IRQS; i++)
+	for (i = 0; i < nr_irqs; i++)
 		lockdep_set_class(&irq_desc[i].lock, &irq_desc_lock_class);
 }