esp_system: remove remaining use of old gdbstub header

Closes https://github.com/espressif/esp-idf/issues/6274

components/esp_common/include/esp_private/gdbstub.h

@@ -1,20 +0,0 @@
-// Copyright 2015-2016 Espressif Systems (Shanghai) PTE LTD
-//
-// Licensed under the Apache License, Version 2.0 (the "License");
-// you may not use this file except in compliance with the License.
-// You may obtain a copy of the License at
-
-//     http://www.apache.org/licenses/LICENSE-2.0
-//
-// Unless required by applicable law or agreed to in writing, software
-// distributed under the License is distributed on an "AS IS" BASIS,
-// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-// See the License for the specific language governing permissions and
-// limitations under the License.
-#pragma once
-
-/* This header exists to avoid making esp_common depend on gdbstub component for panic handler support */
-
-typedef void esp_gdbstub_frame_t;
-
-void esp_gdbstub_panic_handler(esp_gdbstub_frame_t *frame) __attribute__((noreturn));