dt-bindings: timer: ingenic,tcu: use absolute path to other schema

Absolute path to other DT schema is preferred over relative one.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Paul Cercueil <paul@crapouillou.net>
Link: https://lore.kernel.org/r/20220726115937.101432-1-krzysztof.kozlowski@linaro.org


Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>