dt-bindings: mfd: Add STM32F7 SDMMC2 rcc entry

STM32F769 SoC provides 2 SDMMC instances, add missing
RCC SDMMC2 entry for it.
Signed-off-by: Patrice Chotard <patrice.chotard@st.com>
Signed-off-by: Alexandre Torgue <alexandre.torgue@st.com>

include/dt-bindings/mfd/stm32f7-rcc.h

@@ -91,6 +91,7 @@
 #define STM32F7_RCC_APB2_TIM8		1
 #define STM32F7_RCC_APB2_USART1		4
 #define STM32F7_RCC_APB2_USART6		5
+#define STM32F7_RCC_APB2_SDMMC2		7
 #define STM32F7_RCC_APB2_ADC1		8
 #define STM32F7_RCC_APB2_ADC2		9
 #define STM32F7_RCC_APB2_ADC3		10