video: auo_k190x: add driver for AUO-K1900 variant

This controller only supports smaller resolutions and only serial
updates, i.e. it has to wait for an update to finish before
starting another one.

Signed-off-by: Heiko Stübner <heiko@sntech.de>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>