dt-bindings: rockchip-thermal: Support the RK3568 SoC compatible

Add a new compatible for the thermal sensor device on RK3568 SoCs.

Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20210506175514.168365-4-ezequiel@collabora.com