dt-bindings: mmc: Convert sdhci-fujitsu to JSON schema

Convert the Fujitsu SDHCI controller IP binding to DT schema format,
and add resets property as optional to support reset control.

Signed-off-by: Kunihiko Hayashi <hayashi.kunihiko@socionext.com>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20221111081033.3813-2-hayashi.kunihiko@socionext.com


Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>