media: adv7180: Only request valids IRQs

i2c_device_probe(), seems to assume that irq = 0 means that there is no
irq to request.

The driver also believes that on the clean path. So lets be consistent
here.

Also make smatch happy.

Fix:
drivers/media/i2c/adv7180.c:1526 adv7180_probe() warn: 'client->irq' from request_threaded_irq() not released on lines: 1526
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

drivers/media/i2c/adv7180.c

@@ -1486,7 +1486,7 @@ static int adv7180_probe(struct i2c_client *client)
 	if (ret)
 		goto err_media_entity_cleanup;
 
-	if (state->irq) {
+	if (state->irq > 0) {
 		ret = request_threaded_irq(client->irq, NULL, adv7180_irq,
 					   IRQF_ONESHOT | IRQF_TRIGGER_FALLING,
 					   KBUILD_MODNAME, state);