ARM: ux500: modify initial levelshifter status

commit 1d8aca9d
"ARM: ux500: fix MMC/SD card regression"
fixed broken the level shifter: it should be default ON
but became default OFF.

Fixes: 1d8aca9d "ARM: ux500: fix MMC/SD card regression"
Reported-and-tested-by: Ulf Hansson <ulf.hansson@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>