DISCO_F769NI: Disable ULPI alternate mode on unused pins

These pins are not connected to the USB PHY, so don't set their
alternate function as such.

Author: Jookia

targets/TARGET_STM/TARGET_STM32F7/TARGET_STM32F769xI/TARGET_DISCO_F769NI/PeripheralPins.c

@@ -523,8 +523,8 @@ MBED_WEAK const PinMap PinMap_USB_HS[] = {
     {PB_12,     USB_HS, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF10_OTG_HS)}, // USB_OTG_HS_ULPI_D5 // Connected to ULPI_D5 [USB3320C-EZK_D5]
     {PB_13,     USB_HS, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF10_OTG_HS)}, // USB_OTG_HS_ULPI_D6 // Connected to ULPI_D6 [USB3320C-EZK_D6]
     {PC_0,      USB_HS, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF10_OTG_HS)}, // USB_OTG_HS_ULPI_STP // Connected to ULPI_STP [USB3320C-EZK_STP]
-    {PC_2,      USB_HS, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF10_OTG_HS)}, // USB_OTG_HS_ULPI_DIR // Connected to ARD_A2
-    {PC_3,      USB_HS, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF10_OTG_HS)}, // USB_OTG_HS_ULPI_NXT
+//    {PC_2,      USB_HS, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF10_OTG_HS)}, // USB_OTG_HS_ULPI_DIR // Connected to ARD_A2
+//    {PC_3,      USB_HS, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF10_OTG_HS)}, // USB_OTG_HS_ULPI_NXT
     {PH_4,      USB_HS, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF10_OTG_HS)}, // USB_OTG_HS_ULPI_NXT // Connected to ULPI_NXT [USB3320C-EZK_NXT]
     {PI_11,     USB_HS, STM_PIN_DATA(STM_MODE_AF_PP, GPIO_PULLUP, GPIO_AF10_OTG_HS)}, // USB_OTG_HS_ULPI_DIR // Connected to ULPI_DIR [USB3320C-EZK_DIR]
 #endif /* MBED_CONF_TARGET_USB_SPEED */