[MTS_MDOT_F411RE] add back SPI3 pins that shouldn't have been removed

Author: mfiore02

targets/TARGET_STM/TARGET_STM32F4/TARGET_MTS_MDOT_F411RE/PeripheralPins.c

@@ -108,18 +108,21 @@ const PinMap PinMap_UART_RX[] = {
 const PinMap PinMap_SPI_MOSI[] = {
     {PA_7,  SPI_1, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF5_SPI1)},
     {PB_15, SPI_2, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF5_SPI2)},
+    {PC_12, SPI_3, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF6_SPI3)},
     {NC,    NC,    0}
 };
 
 const PinMap PinMap_SPI_MISO[] = {
     {PA_6,  SPI_1, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF5_SPI1)},
     {PB_14, SPI_2, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF5_SPI2)},
+    {PC_11, SPI_3, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF6_SPI3)},
     {NC,    NC,    0}
 };
 
 const PinMap PinMap_SPI_SCLK[] = {
     {PA_5,  SPI_1, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF5_SPI1)},
     {PB_13, SPI_2, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF5_SPI2)},
+    {PC_10, SPI_3, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF6_SPI3)},
     {NC,    NC,    0}
 };