Input: joystick - add ADC attached joystick driver.

Add a driver for joystick devices connected to ADC controllers
supporting the Industrial I/O subsystem.

Signed-off-by: Artur Rojek <contact@artur-rojek.eu>
Tested-by: Paul Cercueil <paul@crapouillou.net>
Tested-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20200927123302.31062-2-contact@artur-rojek.eu


Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>