mmc: sh_mmcif: Remove unused ccs_unsupported from the platform data

mmc: sh_mmcif: Remove unused ccs_unsupported from the platform data

There are currently no users of the ccs_unsupported member from the
platform data, so let's remove it.

Note, as some of the sh_mmcif variants may not support ccs, let's keep the
current code in the driver, which deals with this. For future support, we
should invent a DT binding instead, but let's leave that until it's needed.

Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>