dt-bindings: rtc: pcf2127: add PCF2131

Add support for new NXP RTC PCF2131.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230622145800.2442116-18-hugo@hugovil.com


Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>