Display error message from topgen in topgen-fusesoc

Signed-off-by: Philipp Wagner <phw@lowrisc.org>
diff --git a/util/topgen-fusesoc.py b/util/topgen-fusesoc.py
index 6f31c79..419dfc9 100644
--- a/util/topgen-fusesoc.py
+++ b/util/topgen-fusesoc.py
@@ -79,6 +79,7 @@
 
     except subprocess.CalledProcessError as e:
         print("topgen failed: " + str(e))
+        print(e.stdout)
         sys.exit(1)
 
     # Create core files.