targets: Use ULPI USB mode for DISCO_F769NI

Author: Jookia

targets/targets.json

@@ -2573,6 +2573,10 @@
             "flash_dual_bank": {
                 "help": "Default board configuration is Single Bank Flash. If you enable Dual Bank with ST Link Utility, set value to 1",
                 "value": "0"
+            },
+            "usb_speed": {
+                "help": "USE_USB_OTG_FS or USE_USB_OTG_HS or USE_USB_HS_IN_FS",
+                "value": "USE_USB_OTG_HS"
             }
         },
         "detect_code": [