mmc: tmio: tmio_mmc_host has .bus_shift

Current .bus_shift is implemented under tmio_mmc_data.
It goes to tmio_mmc_host by this patch.

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Acked-by: Lee Jones <lee.jones@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>