dt-bindings: auxdisplay: Add Titan Micro Electronics TM1628

Add a YAML schema binding for TM1628 auxdisplay
(7/11-segment LED) controller.

This patch is partially based on previous work from
Andreas Färber <afaerber@suse.de>.

Co-developed-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Andreas Färber <afaerber@suse.de>
Signed-off-by: Heiner Kallweit <hkallweit1@gmail.com>
Reviewed-by: Rob Herring <robh@kernel.org>