ARM: multi_v7_defconfig: enable STM32 booster regulator

This enables the driver for STM32 booster regulator found on stm32mp1.
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

arch/arm/configs/multi_v7_defconfig

@@ -570,6 +570,7 @@ CONFIG_REGULATOR_RK808=y
 CONFIG_REGULATOR_RN5T618=y
 CONFIG_REGULATOR_S2MPS11=y
 CONFIG_REGULATOR_S5M8767=y
+CONFIG_REGULATOR_STM32_BOOSTER=m
 CONFIG_REGULATOR_STM32_VREFBUF=m
 CONFIG_REGULATOR_STPMIC1=y
 CONFIG_REGULATOR_TI_ABB=y