staging: iio: fix coding style

As suggested by checkpatch.pl, use dev_info() instead of
printk(KERN_INFO ...) to print message.
Signed-off-by: NJoel Porquet <joel@porquet.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/iio/trigger/iio-trig-periodic-rtc.c

@@ -33,7 +33,8 @@ static int iio_trig_periodic_rtc_set_state(struct iio_trigger *trig, bool state)
 	struct iio_prtc_trigger_info *trig_info = iio_trigger_get_drvdata(trig);
 	if (trig_info->frequency == 0)
 		return -EINVAL;
-	printk(KERN_INFO "trigger frequency is %d\n", trig_info->frequency);
+	dev_info(&trig_info->rtc->dev, "trigger frequency is %d\n",
+			trig_info->frequency);
 	return rtc_irq_set_state(trig_info->rtc, &trig_info->task, state);
 }