Based on:
- 3320A in-kernel driver
- https://www.spinics.net/lists/linux-iio/msg25145.html
- https://lore.kernel.org/patchwork/patch/684179/

I decided to keep it aside of AL3320A due to different approach and much
simpler design of 3010.

Tested on Nexus 7 2012 (grouper/tilapia).
Tested-by: David Heidelberg <david@ixit.cz>
Tested-by: Dmitry Osipenko <digetx@gmail.com>
Tested-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
Reviewed-by: Dmitry Osipenko <digetx@gmail.com>
Signed-off-by: David Heidelberg <david@ixit.cz>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>