dt-bindings: watchdog: allow "timer" as node name

On some SoCs the watchdog device is actually mixed with timer, e.g.
the qcom,msm-timer on older Qualcomm SoCs where this is actually one
hardware block responsible for both system timer and watchdog.

Allow calling such device nodes as "timer".

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20221212174933.208900-1-krzysztof.kozlowski@linaro.org


Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>