PM / devfreq: Replace strncpy with strscpy

GCC produces this warning when kernel compiled using `make W=1`:

  warning: ‘strncpy’ specified bound 16 equals destination size [-Wstringop-truncation]
  772 |  strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);

The strncpy doesn't take care of NULL-termination of the destination
buffer, while the strscpy does.
Signed-off-by: NDmitry Osipenko <digetx@gmail.com>
Signed-off-by: NChanwoo Choi <cw00.choi@samsung.com>

drivers/devfreq/devfreq.c

@@ -768,7 +768,7 @@ struct devfreq *devfreq_add_device(struct device *dev,
 	devfreq->dev.release = devfreq_dev_release;
 	INIT_LIST_HEAD(&devfreq->node);
 	devfreq->profile = profile;
-	strncpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
+	strscpy(devfreq->governor_name, governor_name, DEVFREQ_NAME_LEN);
 	devfreq->previous_freq = profile->initial_freq;
 	devfreq->last_status.current_frequency = profile->initial_freq;
 	devfreq->data = data;