dt-bindings: sc16is7xx: convert to YAML

Convert binding from text format to YAML.

Additions to original text binding:
  - add rs485 reference.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230927160153.2717788-3-hugo@hugovil.com


Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>