sh: kfr2r09: use MMC_CAP2_NO_WRITE_PROTECT instead of TMIO own flag

TMIO_MMC_WRPROTECT_DISABLE is equivalent to MMC_CAP2_NO_WRITE_PROTECT.

The flag is propagated as follows:
    tmio_mmc_data::capabilities2 -> mmc_host::caps2

Only the difference is the TMIO_... makes tmio_mmc_get_ro() return 0
(i.e. it does not affect mmc_gpio_get_ro() at all), while MMC_CAP2_...
returns 0 before calling ->get_ro() hook (i.e. it affects both IP own
logic and GPIO detection).

The TMIO MMC drivers do not set-up gpio_ro by themselves, so gpio_ro
is obviously unused by legacy boards like this.  So, this conversion
should be safe.

Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Wolfram Sang <wsa+renesas@sang-engineering.com>