mmc: sh_mobile_sdhi: don't use array for DT configs

We won't access an index based array to get our DT config, but create
separate structs instead. So, remove the array which only wastes memory.

Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>