This reverts commit ce16feb8.

This commit stopped tying down the name of the MMC/SD devices, but these
names are used in the pin control table, so the MMC/SD cards stopped
working.

Cc: Lee Jones <lee.jones@linaro.org>
Reviewed-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>