dt-bindings: mmc: samsung,s3c6410-sdhci: convert to dtschema

Convert the Samsung SoC SDHCI Controller bindings to DT schema.

The original bindings were quite old and incomplete, so add during
conversion typical (already used) properties like reg, clocks,
interrupts.

The bindings were not precising the clocks, although the upstream DTS
and Linux driver were expecting bus clocks in certain patterns in any
order.  Document the status quo even though it is not a proper approach
for bindings.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20220626120342.38851-6-krzysztof.kozlowski@linaro.org
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>