iio: dummy_evgen: fix possible memleak in evgen init

The memory allocated in the function iio_dummy_evgen_create is not
released if it fails to add the evgen device to device hierarchy. This
may result in a memory leak bug.
Signed-off-by: Pan Bian <bianpan2016@163.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/dummy/iio_dummy_evgen.c

@@ -196,7 +196,10 @@ static __init int iio_dummy_evgen_init(void)
 		return ret;
 	device_initialize(&iio_evgen_dev);
 	dev_set_name(&iio_evgen_dev, "iio_evgen");
-	return device_add(&iio_evgen_dev);
+	ret = device_add(&iio_evgen_dev);
+	if (ret)
+		put_device(&iio_evgen_dev);
+	return ret;
 }
 module_init(iio_dummy_evgen_init);