Merge pull request #1338 from petermm/fix-usb-serial

ESP32-S2: fix compilation with USE_USB_SERIAL

Compiling with USE_USB_SERIAL for usb console on s2, would fail as
init_usb_serial() is defined after it's called.

Safe for 0.6.5 inclusion.

These changes are made under both the "Apache 2.0" and the "GNU Lesser General
Public License 2.1 or later" license terms (dual license).

SPDX-License-Identifier: Apache-2.0 OR LGPL-2.1-or-later

src/platforms/esp32/main/main.c

@@ -41,6 +41,7 @@
 // idf.py add-dependency esp_tinyusb
 // and enable CDC in menu config
 #ifdef USE_USB_SERIAL
+void init_usb_serial(void);
 #include "tinyusb.h"
 #include "tusb_cdc_acm.h"
 #include "tusb_console.h"