HID: nvidia-shield: Fix a missing led_classdev_unregister() in the probe error handling path

The commit in Fixes updated the error handling path of
thunderstrike_create() and the remove function but not the error handling
path of shield_probe(), should an error occur after a successful
thunderstrike_create() call.

Add the missing call. Make sure it is safe to call in the probe error
handling path by preventing the led_classdev from attempting to set the LED
brightness to the off state on unregister.

Fixes: f88af60 ("HID: nvidia-shield: Support LED functionality for Thunderstrike")
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Reviewed-by: Rahul Rameshbabu <rrameshbabu@nvidia.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

Author: tititiou36

drivers/hid/hid-nvidia-shield.c

@@ -801,7 +801,7 @@ static inline int thunderstrike_led_create(struct thunderstrike *ts)
 	led->name = devm_kasprintf(&ts->base.hdev->dev, GFP_KERNEL,
 				   "thunderstrike%d:blue:led", ts->id);
 	led->max_brightness = 1;
-	led->flags = LED_CORE_SUSPENDRESUME;
+	led->flags = LED_CORE_SUSPENDRESUME | LED_RETAIN_AT_SHUTDOWN;
 	led->brightness_get = &thunderstrike_led_get_brightness;
 	led->brightness_set = &thunderstrike_led_set_brightness;
 
@@ -1076,6 +1076,7 @@ static int shield_probe(struct hid_device *hdev, const struct hid_device_id *id)
 err_haptics:
 	if (ts->haptics_dev)
 		input_unregister_device(ts->haptics_dev);
+	led_classdev_unregister(&ts->led_dev);
 	return ret;
 }