dt-bindings: watchdog: faraday: Fix typo in example 'timeout-sec' property

The 'unevaluatedProperties' schema checks is not fully working and doesn't
catch some cases where there's a $ref to another schema. A fix is pending,
but results in new warnings in examples.

The correct common watchdog property is 'timeout-sec', not 'timeout-secs'.

Signed-off-by: Rob Herring <robh@kernel.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220526014127.2872254-1-robh@kernel.org