linux-imx

mmc: mmci: add optional reset property

This patch adds a optional reset management.
STM32 sdmmc variant needs to reset hardware block
during the power cycle procedure (for re-initialization).

Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>