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/spurious.c b/kernel/irq/spurious.c
index 19fe9d6..e26ca1e 100644
--- a/kernel/irq/spurious.c
+++ b/kernel/irq/spurious.c
@@ -91,7 +91,7 @@
 	int i;
 	int ok = 0;
 
-	for (i = 1; i < NR_IRQS; i++) {
+	for (i = 1; i < nr_irqs; i++) {
 		struct irq_desc *desc = irq_desc + i;
 
 		if (i == irq)	/* Already tried */
@@ -107,7 +107,7 @@
 static void poll_spurious_irqs(unsigned long dummy)
 {
 	int i;
-	for (i = 1; i < NR_IRQS; i++) {
+	for (i = 1; i < nr_irqs; i++) {
 		struct irq_desc *desc = irq_desc + i;
 		unsigned int status;