dt-bindings: Correct indentation and style in DTS example

DTS example in the bindings should be indented with 2- or 4-spaces and
aligned with opening '- |', so correct any differences like 3-spaces or
mixtures 2- and 4-spaces in one binding.

No functional changes here, but saves some comments during reviews of
new patches built on existing code.

Acked-by: Ulf Hansson <ulf.hansson@linaro.org> # For MMC
Acked-by: Lee Jones <lee@kernel.org>
Acked-by: Thierry Reding <treding@nvidia.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> # renesas
Link: https://lore.kernel.org/r/20250107131456.247610-1-krzysztof.kozlowski@linaro.org


Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20250725100241.120106-2-krzysztof.kozlowski@linaro.org


Signed-off-by: Rob Herring (Arm) <robh@kernel.org>