dt-bindings: watchdog: da9062-wdt: convert txt to yaml

Convert txt file to yaml.
Add a mainterner block. Took a value from dlg,da9063 PMIC.

Signed-off-by: Nik Bune <n2h9z4@gmail.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20231014170434.159310-1-n2h9z4@gmail.com
Signed-off-by: Rob Herring <robh@kernel.org>