dt-bindings: mmc: brcm,sdhci-brcmstb: cleanup example

Cleanup indentation and order of entries in example DTS.  The most
important when reading the DTS are compatible and reg.  By convention
they are usually to first entries.  No functional change.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Acked-by: Florian Fainelli <f.fainelli@gmail.com>
Link: https://lore.kernel.org/r/20220428081817.35382-2-krzysztof.kozlowski@linaro.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>