stm32/usbd_conf: Allow boards to configure USB HS ULPI NXT/DIR pins.

ports/stm32/boards/STM32F769DISC/mpconfigboard.h

@@ -102,6 +102,8 @@ extern struct _spi_bdev_t spi_bdev;
 
 // USB config (CN15 - USB OTG HS with external PHY)
 #define MICROPY_HW_USB_HS (1)
+#define MICROPY_HW_USB_HS_ULPI_NXT  (pin_H4)
+#define MICROPY_HW_USB_HS_ULPI_DIR  (pin_I11)
 
 // Ethernet via RMII
 #define MICROPY_HW_ETH_MDC          (pin_C1)

ports/stm32/usbd_conf.c

@@ -171,7 +171,7 @@ void HAL_PCD_MspInit(PCD_HandleTypeDef *hpcd) {
 
         // Configure USB HS GPIOs
         static const mp_hal_pin_obj_t usb_pins[] = {
-            pin_A5, pin_C0, pin_H4, pin_I11, // CLK, STP, NXT, DIR
+            pin_A5, pin_C0, MICROPY_HW_USB_HS_ULPI_NXT, MICROPY_HW_USB_HS_ULPI_DIR, // CLK, STP, NXT, DIR
             pin_A3, pin_B0, pin_B1, pin_B5, pin_B10, pin_B11, pin_B12, pin_B13, // D0-D7
         };
         for (size_t i = 0; i < MP_ARRAY_SIZE(usb_pins); ++i) {