mmc: mmci_sdmmc: Rename sdmmc_priv struct to sdmmc_idma

This patch renames sdmmc_priv struct to sdmmc_idma which is assigned to
host->dma_priv.

Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
Link: https://lore.kernel.org/r/20200128090636.13689-3-ludovic.barre@st.com


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