Add MMC YAML file for Sunplus SP7021.
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Tony Huang <tonyhuang.sunplus@gmail.com>
Link: https://lore.kernel.org/r/8c8fbc29524819d8ab45a4fe75311b3b7b567650.1669023361.git.tonyhuang.sunplus@gmail.comSigned-off-by: Ulf Hansson <ulf.hansson@linaro.org>