i2c/ibm-iic: Drop NO_IRQ

Drop NO_IRQ as 0 is the preferred way to describe 'no irq'
(http://lkml.org/lkml/2005/11/21/221). This change is safe, as the driver is
only used on powerpc, where NO_IRQ is 0 anyhow.

Signed-off-by: Wolfram Sang <[e-mail]>
Acked-by: Grant Likely <[e-mail]>
Cc: Sean MacLennan <[e-mail]>
Cc: Ben Dooks <[e-mail]>
Acked-by: Sean MacLennan <[e-mail]>
Signed-off-by: Benjamin Herrenschmidt <[e-mail]>

drivers/i2c/busses/i2c-ibm_iic.c

···
 	int irq;
 
 	if (iic_force_poll)
-		return NO_IRQ;
+		return 0;
 
 	irq = irq_of_parse_and_map(np, 0);
-	if (irq == NO_IRQ) {
+	if (!irq) {
 		dev_err(&ofdev->dev, "irq_of_parse_and_map failed\n");
-		return NO_IRQ;
+		return 0;
 	}
 
 	/* Disable interrupts until we finish initialization, assumes
···
 	if (request_irq(irq, iic_handler, 0, "IBM IIC", dev)) {
 		dev_err(&ofdev->dev, "request_irq %d failed\n", irq);
 		/* Fallback to the polling mode */
-		return NO_IRQ;
+		return 0;
 	}
 
 	return irq;
···
 	init_waitqueue_head(&dev->wq);
 
 	dev->irq = iic_request_irq(ofdev, dev);
-	if (dev->irq == NO_IRQ)
+	if (!dev->irq)
 		dev_warn(&ofdev->dev, "using polling mode\n");
 
 	/* Board specific settings */
···
 	return 0;
 
 error_cleanup:
-	if (dev->irq != NO_IRQ) {
+	if (dev->irq) {
 		iic_interrupt_mode(dev, 0);
 		free_irq(dev->irq, dev);
 	}
···
 
 	i2c_del_adapter(&dev->adap);
 
-	if (dev->irq != NO_IRQ) {
+	if (dev->irq) {
 		iic_interrupt_mode(dev, 0);
 		free_irq(dev->irq, dev);
 	}