dt-bindings: iio: maxbotix,mb1232.yaml: transform to yaml

transform existing documentation of maxbotix,mb1232 ultrasonic ranger
from text documentation format into yaml.

Changes in v3:
- add a i2c node around device node to set up #address-cells and
  #size-cells for omitting error during make dt_binding_check

Changes in v2:
- removed description of reg property
- added a line:
  additionalProperties: false

Signed-off-by: Andreas Klinger <ak@it-klinger.de>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>