mmc: mmci: Add a reference at mmc_host_ops in mmci struct

The variant init function may need to add a mmc_host_ops, for example to
add the execute_tuning support if this feature is available. This patch
adds mmc_host_ops pointer in mmci struct.

Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
Link: https://lore.kernel.org/r/20200128090636.13689-4-ludovic.barre@st.com


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