dt-bindings: rtc: convert trivial devices into dtschema

dt-bindings: rtc: convert trivial devices into dtschema

These RTCs meet the requirements for a direct conversion into
trivial-rtc:

- google,goldfish-rtc
- maxim,ds1742
- lpc32xx-rtc
- orion-rtc
- rtc-aspeed
- spear-rtc
- via,vt8500-rtc

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Andrew Jeffery <andrew@codeconstruct.com.au>
Signed-off-by: Javier Carrasco <javier.carrasco.cruz@gmail.com>
Link: https://lore.kernel.org/r/20240413-rtc_dtschema-v3-2-eff368bcc471@gmail.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>