iio: potentiostat: Drop unnecessary -ENOMEM messages

The drivers do not require their own error messages for error
-ENOMEM, memory allocation failures. So remove the dev_err()
messages from the probe().

Signed-off-by: Dixit Parmar <[e-mail]>
Link: https://patch.msgid.link/[e-mail]
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/potentiostat/lmp91000.c

···
 	data->trig = devm_iio_trigger_alloc(dev, "%s-mux%d",
 					    indio_dev->name,
 					    iio_device_id(indio_dev));
-	if (!data->trig) {
-		dev_err(dev, "cannot allocate iio trigger.\n");
+	if (!data->trig)
 		return -ENOMEM;
-	}
 
 	init_completion(&data->completion);