mmc: dw_mmc: Add support for platform specific eMMC HW reset

This commit adds a new callback to allow drivers to support platform
specific eMMC HW reset.

Reviewed-by: David Thompson <davthompson@nvidia.com>
Signed-off-by: Liming Sun <limings@nvidia.com>
Link: https://lore.kernel.org/r/3df02ffa8bdaa74f5261c8914d2545b97fb3478a.1718213918.git.limings@nvidia.com


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