iio: magnetometer: ak8974: add_device_randomness (serial number)

Mix device-specific data into randomness pool.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
1 file changed