samples: Bluetooth: df: rx: Add info about nRF5340 to README.rst

Extend README.rst with information about support for nRF5340.

Signed-off-by: Piotr Pryga <[email protected]>

Author: ppryga-nordic

samples/bluetooth/direction_finding_connectionless_rx/README.rst

@@ -16,7 +16,7 @@ The sample supports the following development kits:
 
 .. table-from-rows:: /includes/sample_board_rows.txt
    :header: heading
-   :rows: nrf52833dk_nrf52833
+   :rows: nrf52833dk_nrf52833, nrf5340dk_nrf5340_cpuapp_and_cpuappns
 
 The sample also requires an antenna matrix when operating in angle of arrival mode.
 It can be a Nordic Semiconductor design 12 patch antenna matrix, or any other antenna matrix.
@@ -38,6 +38,15 @@ Configuration
 
 |config|
 
+This sample configuration is split into the following two files:
+
+* generic configuration is available in :file:`prj.conf` file
+* board specific configuration is available in :file:`boards/<BOARD>.conf` file
+
+Board specific configuration involves configuring the Bluetooth LE controller.
+For :ref:`nRF5340 DK <ug_nrf5340>`, the Bluetooth LE controller is part of a ``child image`` aimed to run on the network core.
+Configuration for the child image is stored in :file:`child_image/` subdirectory.
+
 Angle of departure mode
 =======================
 
@@ -46,6 +55,8 @@ To build this sample with angle of departure mode only, set ``OVERLAY_CONFIG`` t
 See :ref:`cmake_options` for instructions on how to add this option.
 For more information about using configuration overlay files, see :ref:`zephyr:important-build-vars` in the Zephyr documentation.
 
+To build this sample for :ref:`nRF5340 DK <ug_nrf5340>`, with angle of arrival mode only, add content of :file:`overlay-aod.conf` file to :file:`child_image/hci_rpmsg.conf` file.
+
 Antenna matrix configuration for angle of arrival mode
 ======================================================