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

Documentation/devicetree/bindings/rtc/nxp,pcf2127.yaml

@@ -18,6 +18,7 @@ properties:
       - nxp,pca2129
       - nxp,pcf2127
       - nxp,pcf2129
+      - nxp,pcf2131
 
   reg:
     maxItems: 1