applications: nrf_desktop: Fix MCUboot serial recovery DFU image path

Change fixes path to DFU update image file in documentation (MCUboot
serial recovery).

Jira: NCSDK-31754

Signed-off-by: Marek Pieta <[email protected]>

Author: MarekPieta

applications/nrf_desktop/bootloader_dfu.rst

@@ -401,13 +401,13 @@ Once the device enters the serial recovery mode, you can use the :ref:`mcumgr <z
 
 * Query information about the present image.
 * Upload the new image.
-  The :ref:`mcumgr <zephyr:device_mgmt>` uses the :file:`<build_dir>/zephyr/nrf_desktop/zephyr.signed.bin` update image file.
+  The :ref:`mcumgr <zephyr:device_mgmt>` uses the :file:`<build_dir>/nrf_desktop/zephyr/zephyr.signed.bin` update image file.
   It is generated by the build system when building the firmware.
 
 For example, the following line starts the upload of the new image to the device:
 
 .. code-block:: console
 
-  mcumgr -t 60 --conntype serial --connstring=/dev/ttyACM0 image upload build-nrf52833dongle/zephyr/nrf_desktop/zephyr.signed.bin
+  mcumgr -t 60 --conntype serial --connstring=/dev/ttyACM0 image upload build/nrf_desktop/zephyr/zephyr.signed.bin
 
 The command assumes that ``/dev/ttyACM0`` serial device is used by the MCUboot bootloader for the serial recovery.