applications: nrf_desktop: doc: dfu_mcumgr: align with IronSide SE

Updated the DFU MCUmgr application module that is part of the
nRF Desktop application to align with the IronSide SE architecture
for the nRF54H20 SoC.

Ref: NCSDK-35488

Signed-off-by: Kamil Piszczek <Kamil.Piszczek@nordicsemi.no>

Author: kapi-no

applications/nrf_desktop/doc/dfu_mcumgr.rst

@@ -69,6 +69,8 @@ Make sure that the DFU lock utility is enabled if your nRF Desktop application c
 You cannot use this module with the :ref:`caf_ble_smp`.
 In other words, you cannot simultaneously enable the :ref:`CONFIG_DESKTOP_DFU_MCUMGR_ENABLE <config_desktop_app_options>` option and the :kconfig:option:`CONFIG_CAF_BLE_SMP` Kconfig option.
 
+Currently, this module supports only one bootloader backend: the MCUboot bootloader backend.
+
 .. note::
     B0 bootloader is not integrated with MCUmgr.
 

doc/nrf/releases_and_maturity/releases/release-notes-changelog.rst

@@ -313,6 +313,9 @@ nRF Desktop
     * The documentation of the :ref:`nrf_desktop_hid_state` and default HID report providers to simplify getting started with updating HID input reports used by the application or introducing support for a new HID input report.
     * The default value of the :kconfig:option:`CONFIG_SOC_FLASH_NRF_RADIO_SYNC_MPSL_NORMAL_PRIORITY_TIMEOUT_US` Kconfig option to ``0``.
       This is done to start using high MPSL timeslot priority quicker and speed up non-volatile memory operations.
+    * The :ref:`nrf_desktop_dfu_mcumgr` to handle the ``nrf54h20dk/nrf54h20/cpuapp`` board target with the IronSide SE architecture and the MCUboot bootloader.
+
+  * Removed the SUIT support from the :ref:`nrf_desktop_dfu_mcumgr`.
 
 nRF Machine Learning (Edge Impulse)
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