dt-bindings: thermal-zones: Don't require polling-delay(-passive)

Currently, thermal zones associated with providers that have interrupts
for signaling hot/critical trips are required to set a polling-delay
of 0 to indicate no polling. This feels a bit backwards.

Assume 0 (no polling) when these properties are not defined.

Signed-off-by: Konrad Dybcio <konrad.dybcio@linaro.org>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Reviewed-by: Bjorn Andersson <andersson@kernel.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Link: https://lore.kernel.org/r/20240125-topic-thermal-v1-1-3c9d4dced138@linaro.org