mmc: core: Add HS400 tuning in HS400es initialization

During the initialization to HS400es stage, add a HS400 tuning flow as an
optional process. For Mediatek IP, the HS400es mode requires a specific
tuning to ensure the correct HS400 timing setting.

Signed-off-by: Mengqi Zhang <mengqi.zhang@mediatek.com>
Link: https://lore.kernel.org/r/20231225093839.22931-2-mengqi.zhang@mediatek.com


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