disable PA_8 i2c pin on NUCLEO_F411RE

pin PA_8 by default is connected to MCO

Author: maciejbocianski

targets/TARGET_STM/TARGET_STM32F4/TARGET_STM32F411xE/TARGET_NUCLEO_F411RE/PeripheralPinMaps.h

@@ -94,7 +94,7 @@ MSTD_CONSTEXPR_OBJ_11 const PinMap PinMap_I2C_SDA[] = {
 };
 
 MSTD_CONSTEXPR_OBJ_11 const PinMap PinMap_I2C_SCL[] = {
-    {PA_8,       I2C_3, STM_PIN_DATA(STM_MODE_AF_OD, GPIO_NOPULL, GPIO_AF4_I2C3)},
+    //{PA_8,       I2C_3, STM_PIN_DATA(STM_MODE_AF_OD, GPIO_NOPULL, GPIO_AF4_I2C3)}, // Connected to MCO
     {PB_6,       I2C_1, STM_PIN_DATA(STM_MODE_AF_OD, GPIO_NOPULL, GPIO_AF4_I2C1)},
     {PB_8,       I2C_1, STM_PIN_DATA(STM_MODE_AF_OD, GPIO_NOPULL, GPIO_AF4_I2C1)},
     {PB_10,      I2C_2, STM_PIN_DATA(STM_MODE_AF_OD, GPIO_NOPULL, GPIO_AF4_I2C2)},