iio: adc: pac1921: 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: 371f778 ("iio: adc: add support for pac1921")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Acked-by: Matteo Martelli <matteomartelli3@gmail.com>
Link: https://patch.msgid.link/20241030162013.2100253-3-andriy.shevchenko@linux.intel.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/adc/pac1921.c

@@ -1170,7 +1170,9 @@ static int pac1921_probe(struct i2c_client *client)
 		return dev_err_probe(dev, PTR_ERR(priv->regmap),
 				     "Cannot initialize register map\n");
 
-	devm_mutex_init(dev, &priv->lock);
+	ret = devm_mutex_init(dev, &priv->lock);
+	if (ret)
+		return ret;
 
 	priv->dv_gain = PAC1921_DEFAULT_DV_GAIN;
 	priv->di_gain = PAC1921_DEFAULT_DI_GAIN;