ARM: at91/defconfig: add CONFIG_REGULATOR_FIXED_VOLTAGE for mmc driver

As an update of the sd/mmc DT definition needs the fixed voltage regulator, add
it to the at91 defconfigs.
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>

arch/arm/configs/at91_dt_defconfig

@@ -131,6 +131,8 @@ CONFIG_POWER_RESET=y
 CONFIG_WATCHDOG=y
 CONFIG_AT91SAM9X_WATCHDOG=y
 CONFIG_SSB=m
+CONFIG_REGULATOR=y
+CONFIG_REGULATOR_FIXED_VOLTAGE=y
 CONFIG_FB=y
 CONFIG_FB_ATMEL=y
 CONFIG_BACKLIGHT_LCD_SUPPORT=y

arch/arm/configs/sama5_defconfig

@@ -136,6 +136,7 @@ CONFIG_POWER_RESET=y
 # CONFIG_HWMON is not set
 CONFIG_SSB=m
 CONFIG_REGULATOR=y
+CONFIG_REGULATOR_FIXED_VOLTAGE=y
 CONFIG_REGULATOR_ACT8865=y
 CONFIG_MEDIA_SUPPORT=y
 CONFIG_MEDIA_CAMERA_SUPPORT=y