i2c/mpc: 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 <w.sang@pengutronix.de>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

drivers/i2c/busses/i2c-mpc.c

@@ -118,7 +118,7 @@ static int i2c_wait(struct mpc_i2c *i2c, unsigned timeout, int writing)
 	u32 x;
 	int result = 0;
 
-	if (i2c->irq == NO_IRQ) {
+	if (!i2c->irq) {
 		while (!(readb(i2c->base + MPC_I2C_SR) & CSR_MIF)) {
 			schedule();
 			if (time_after(jiffies, orig_jiffies + timeout)) {
@@ -568,7 +568,7 @@ static int __devinit fsl_i2c_probe(struct of_device *op,
 	}
 
 	i2c->irq = irq_of_parse_and_map(op->node, 0);
-	if (i2c->irq != NO_IRQ) { /* i2c->irq = NO_IRQ implies polling */
+	if (i2c->irq) { /* no i2c->irq implies polling */
 		result = request_irq(i2c->irq, mpc_i2c_isr,
 				     IRQF_SHARED, "i2c-mpc", i2c);
 		if (result < 0) {
@@ -627,7 +627,7 @@ static int __devexit fsl_i2c_remove(struct of_device *op)
 	i2c_del_adapter(&i2c->adap);
 	dev_set_drvdata(&op->dev, NULL);
 
-	if (i2c->irq != NO_IRQ)
+	if (i2c->irq)
 		free_irq(i2c->irq, i2c);
 
 	irq_dispose_mapping(i2c->irq);