ASoC: dt-bindings: cirrus,cs35l41: cleanup $ref and example

Non-functional cleanup:
1. Drop unneeded quotes form $ref,
2. Example: Use generic node name, use define for GPIO flag, adjust
   indentation to consistent 4-space style.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Charles Keepax <ckeepax@opensource.cirrus.com>
Link: https://lore.kernel.org/r/20221224154210.43356-2-krzysztof.kozlowski@linaro.org
Signed-off-by: Mark Brown <broonie@kernel.org>