samples: gdbstub: doc: Remove redundant sample

Example

*******

This is an example using ``samples/subsys/debug/gdbstub`` to demonstrate

how GDB stub works.

This is an example to demonstrate how GDB stub works.

You can also refer to ``tests/subsys/debug/gdbstub``

for its implementation as a Twister test.

#. Open two terminal windows.

# SPDX-License-Identifier: Apache-2.0

cmake_minimum_required(VERSION 3.20.0)

if(BOARD MATCHES "qemu_x86")

  list(APPEND QEMU_EXTRA_FLAGS -serial tcp:127.0.0.1:5678,server)

endif()

find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})

project(debug)

target_sources(app PRIVATE src/main.c)

.. zephyr:code-sample:: gdb-debug

   :name: GDB debug

   Use GDB Remote Serial Protocol to debug a Zephyr application running on QEMU.

Overview

********

A simple sample that can be used with QEMU to show debug using GDB

Remote Serial Protocol (RSP) capabilities.

Building and Running

********************

This application can be built and executed on QEMU as follows:

.. zephyr-app-commands::

   :zephyr-app: samples/subsys/debug/gdbstub

   :host-os: unix

   :board: qemu_x86

   :goals: run

   :compact:

Open a new terminal and use gdb to connect to the running qemu as follows:

.. code-block:: bash

    gdb build/zephyr/zephyr.elf

    (gdb) target remote :5678

Exit QEMU by pressing :kbd:`CTRL+A` :kbd:`x`.

/* SPDX-License-Identifier: Apache-2.0 */

/ {

	chosen {

		zephyr,gdbstub-uart = &uart1;

	};

};

/* SPDX-License-Identifier: Apache-2.0 */

/ {

	chosen {

		zephyr,gdbstub-uart = &uart1;

	};

};