leds: st1202: Check for error code from devm_mutex_init() call

Even if it's not critical, the avoidance of checking the error code
from devm_mutex_init() call today diminishes the point of using devm
variant of it. Tomorrow it may even leak something. Add the missed
check.

Fixes: 2592303 ("leds: Add LED1202 I2C driver")
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Link: https://lore.kernel.org/r/20250204-must_check-devm_mutex_init-v2-1-7b6271c4b7e6@weissschuh.net
Signed-off-by: Lee Jones <lee@kernel.org>

Author: t-8ch

drivers/leds/leds-st1202.c

@@ -356,7 +356,9 @@ static int st1202_probe(struct i2c_client *client)
 	if (!chip)
 		return -ENOMEM;
 
-	devm_mutex_init(&client->dev, &chip->lock);
+	ret = devm_mutex_init(&client->dev, &chip->lock);
+	if (ret < 0)
+		return ret;
 	chip->client = client;
 
 	ret = st1202_dt_init(chip);