Config: Add stm targets in single entry point

This patch allows to group all stm targets in single cmake entry point.
The stm TARGET_PLATFORM should prefix by "STM".
stm platforms supports CoreIPC, CoreIPCTfmLevel2 and RegressionIPCTfmLevel2
Build with GNUARM toolchain.

Change-Id: I6535420b2304c18f2ab260620c38fef632eb7488
Signed-off-by: Ludovic Barre <ludovic.barre@st.com>
Signed-off-by: Michel Jaouen <michel.jaouen@st.com>
diff --git a/docs/user_guides/tfm_sw_requirement.rst b/docs/user_guides/tfm_sw_requirement.rst
index d9f0ac8..ca8688e 100644
--- a/docs/user_guides/tfm_sw_requirement.rst
+++ b/docs/user_guides/tfm_sw_requirement.rst
@@ -137,6 +137,14 @@
    `CMSIS release notes <https://github.com/ARM-software/CMSIS_5/releases>`__.
    for guidance.
 
+********************************************
+Tools for configuring and programming boards
+********************************************
+
+For stm32l5xx boards, `STM32_Programmer_CLI  <https://www.st.com/en/development-tools/stm32cubeprog.html>`__ 
+is used to configure security protections and to write the code in internal flash.
+A version is available for Linux and Windows host machine.
+
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 Example setups
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