ARM: ux500: Remove redundant board file for mmci platform data

Since all platform data has been transfered to DT, we don't need the
container for the mmci platform data anymore. Remove the file and the
corresponding references to it's data.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>