ARM: multi_v7_defconfig: enable STM32 dfsdm audio support

Add STM32 DFSDM audio support by enabling CONFIG_SND_SOC_STM32_DFSDM
as module.
Signed-off-by: Olivier Moysan <olivier.moysan@st.com>
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Signed-off-by: Alexandre Torgue <alexandre.torgue@foss.st.com>

arch/arm/configs/multi_v7_defconfig

@@ -743,6 +743,7 @@ CONFIG_SND_SOC_STI=m
 CONFIG_SND_SOC_STM32_SAI=m
 CONFIG_SND_SOC_STM32_I2S=m
 CONFIG_SND_SOC_STM32_SPDIFRX=m
+CONFIG_SND_SOC_STM32_DFSDM=m
 CONFIG_SND_SUN4I_CODEC=m
 CONFIG_SND_SOC_TEGRA=m
 CONFIG_SND_SOC_TEGRA20_I2S=m