pa_laser_ping_cfg should be set in of_ping_match
instead of pa_ping_cfg.

Fixes: 7bb501f4 ("iio: ping: add parallax ping sensors")
Signed-off-by: YueHaibing <yuehaibing@huawei.com>
Acked-by: Andreas Klinger <ak@it-klinger.de>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>