leds: trigger: netdev: reject interval store for hw_control

Reject interval store with hw_control enabled. It's are currently not
supported and MUST be set to the default value with hw control enabled.
Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/leds/trigger/ledtrig-netdev.c

@@ -265,6 +265,9 @@ static ssize_t interval_store(struct device *dev,
 	unsigned long value;
 	int ret;
 
+	if (trigger_data->hw_control)
+		return -EINVAL;
+
 	ret = kstrtoul(buf, 0, &value);
 	if (ret)
 		return ret;