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>