dt-bindings: rtc: pcf8523: Convert to YAML

Convert the PCF8523 bindings from text format to YAML.

The YAML format is preferred as it allows validation.

Signed-off-by: Fabio Estevam <festevam@denx.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20230905220826.79901-1-festevam@gmail.com


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