ARM: ux500: CONFIG: Enable GPIO Regulators

It is the intention to convert the MMC voltage changing from
GPIO flipping to using a proper GPIO regulator interface. A
prerequisite of that is to enable the GPIO regulator
functionality. As this affects all ux5x0 based boards we'll
do it here instead of in the Kconfigs.
Acked-by: NLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: NLee Jones <lee.jones@linaro.org>

arch/arm/configs/u8500_defconfig

@@ -76,6 +76,7 @@ CONFIG_AB8500_CORE=y
 CONFIG_REGULATOR=y
 CONFIG_REGULATOR_AB8500=y
 CONFIG_REGULATOR_FIXED_VOLTAGE=y
+CONFIG_REGULATOR_GPIO=y
 # CONFIG_HID_SUPPORT is not set
 CONFIG_USB_GADGET=y
 CONFIG_AB8500_USB=y