dt-bindings: watchdog: atmel,at91rm9200-wdt: convert txt to yaml

Convert txt file to yaml.

Signed-off-by: Nik Bune <n2h9z4@gmail.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230924181959.64264-1-n2h9z4@gmail.com


Signed-off-by: Rob Herring <robh@kernel.org>