[CI] Fix exception syntax

Signed-off-by: Frederic Pillon <frederic.pillon@st.com>

Author: fpistm

CI/build/arduino-cli.py

@@ -468,7 +468,7 @@ def find_board():
             else:
                 raise subprocess.CalledProcessError(1, "No fqbn")
         except subprocess.CalledProcessError as e:
-            print("No fqbn detail found for " + e.cmd + "!")
+            print("No fqbn detail found for:\"" + " ".join(e.cmd) + "\"!")
     if board_found:
         board_fqbn = collections.OrderedDict(sorted(board_found.items()))
     else: