ARM: configs: stm32: Add DMAMUX support in STM32 defconfig

This patch adds DMAMUX support in STM32 defconfig file
Signed-off-by: M'boumba Cedric Madianga <cedric.madianga@gmail.com>
Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

arch/arm/configs/stm32_defconfig

@@ -65,6 +65,7 @@ CONFIG_RTC_CLASS=y
 CONFIG_RTC_DRV_STM32=y
 CONFIG_DMADEVICES=y
 CONFIG_STM32_DMA=y
+CONFIG_STM32_DMAMUX=y
 CONFIG_IIO=y
 CONFIG_STM32_ADC_CORE=y
 CONFIG_STM32_ADC=y