i2c: i2c-stm32f7: Add slave support

This patch adds slave support for I2C controller embedded in STM32F7 SoC
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: Wolfram Sang <wsa@the-dreams.de>

drivers/i2c/busses/Kconfig

@@ -944,6 +944,7 @@ config I2C_STM32F4
 config I2C_STM32F7
 	tristate "STMicroelectronics STM32F7 I2C support"
 	depends on ARCH_STM32 || COMPILE_TEST
+	select I2C_SLAVE
 	help
 	  Enable this option to add support for STM32 I2C controller embedded
 	  in STM32F7 SoCs.