dt-bindings: rockchip-thermal: Support the PX30 SoC compatible

Add a new compatible for thermal founding on PX30 SoCs.

Signed-off-by: Elaine Zhang <zhangqing@rock-chips.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Eduardo Valentin <edubezval@gmail.com>