dt-bindings: thermal: st,stm32: reference thermal-sensor schema

dt-bindings: thermal: st,stm32: reference thermal-sensor schema

Device is a thermal sensor and it requires '#thermal-sensor-cells', so
reference the thermal-sensor.yaml to simplify it and bring the
common definition of '#thermal-sensor-cells' property.

Acked-by: Conor Dooley <conor.dooley@microchip.com>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240705-dt-bindings-thermal-allof-v1-18-554061b52fbc@linaro.org
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>