ARM: ux500: Move GPIO regulator for SD-card into board DTSs

The GPIO regulator for the SD-card isn't a ux500 SOC configuration, but
instead it's specific to the board. Move the definition of it, into the
board DTSs.

Fixes: c94a4ab7

 ("ARM: ux500: Disable the MMCI gpio-regulator by default")
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Reviewed-by: Bjorn Andersson <bjorn.andersson@sonymobile.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>