doc: Mention "commander" and "Jlink" package

Commander is needed to flash SiWx917. So, explain how to install
commander in `README`.

Also add the commands to automate the installation (ie. for Docker
images).

Signed-off-by: Jérôme Pouiller <[email protected]>

Author: jerome-pouiller

README.md

@@ -32,10 +32,25 @@ TL;DR:
     cd zephyr-sdk-0.16.8
     ./setup.sh
 
+[Install J-Link software pack][3]:
+
+    curl --data-raw accept_license_agreement=accepted https://www.segger.com/downloads/jlink/JLink_Linux_$(uname -m).deb -o JLink_Linux_$(uname -m).deb
+    sudo dpkg -i JLink_Linux_$(uname -m).deb
+
+[Install Simplicity Commander][4]:
+
+    cd /tmp
+    wget https://www.silabs.com/documents/login/software/SimplicityCommander-Linux.zip
+    unzip SimplicityCommander-Linux.zip
+    sudo tar -C /opt -xvf /tmp/SimplicityCommander-Linux/Commander_linux_$(uname -m)_*.tar.bz
+    sudo ln -sfn /opt/commander/commander /usr/local/bin/
+
 Build an application:
 
     west build -b siwx917_rb4338a zephyr/samples/hello_world
 
 
 [1]: https://docs.zephyrproject.org/latest/develop/west/install.html
 [2]: https://docs.zephyrproject.org/latest/develop/toolchains/index.html
+[3]: https://www.segger.com/jlink-software.html
+[4]: https://www.silabs.com/developers/simplicity-studio/simplicity-commander?tab=downloads