platform: stm: Add board b_u585i_iot02a

Change-Id: I0fad29f8eb92cc695461521eea93ff4472e48c9e
Signed-off-by: Michel Jaouen <michel.jaouen@st.com>
diff --git a/platform/ext/target/stm/index.rst b/platform/ext/target/stm/index.rst
index b974c9a..cb1c853 100644
--- a/platform/ext/target/stm/index.rst
+++ b/platform/ext/target/stm/index.rst
@@ -18,6 +18,7 @@
 
     nucleo*/**
     stm32*/**
+    b_*/**
 
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