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/resend.c b/kernel/irq/resend.c
index a804679..cba8aa5 100644
--- a/kernel/irq/resend.c
+++ b/kernel/irq/resend.c
@@ -33,8 +33,8 @@
 	struct irq_desc *desc;
 	int irq;
 
-	while (!bitmap_empty(irqs_resend, NR_IRQS)) {
-		irq = find_first_bit(irqs_resend, NR_IRQS);
+	while (!bitmap_empty(irqs_resend, nr_irqs)) {
+		irq = find_first_bit(irqs_resend, nr_irqs);
 		clear_bit(irq, irqs_resend);
 		desc = irq_desc + irq;
 		local_irq_disable();