drivers/serial: use nr_irqs

Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/drivers/serial/amba-pl010.c b/drivers/serial/amba-pl010.c
index 90b56c2..7156268 100644
--- a/drivers/serial/amba-pl010.c
+++ b/drivers/serial/amba-pl010.c
@@ -512,7 +512,7 @@
 	int ret = 0;
 	if (ser->type != PORT_UNKNOWN && ser->type != PORT_AMBA)
 		ret = -EINVAL;
-	if (ser->irq < 0 || ser->irq >= NR_IRQS)
+	if (ser->irq < 0 || ser->irq >= nr_irqs)
 		ret = -EINVAL;
 	if (ser->baud_base < 9600)
 		ret = -EINVAL;