MCU Support: Show deployment issues in issues pane

MCU deployment issues will be shown in the Issues output pane.

Change-Id: I5b3751d65a8e46e24a68591f9a0c6f7f77492324
Reviewed-by: Sivert Krøvel <sivert.krovel@qt.io>
Reviewed-by: Thomas Hartmann <thomas.hartmann@qt.io>

src/plugins/mcusupport/mcubuildstep.cpp

@@ -100,6 +100,11 @@ DeployMcuProcessStep::DeployMcuProcessStep(ProjectExplorer::BuildStepList *bc, I
         cmdLine.addArg(directory);
         return cmdLine;
     });
+
+    connect(this, &BuildStep::addOutput, this, [](const QString &str, OutputFormat fmt) {
+        if (fmt == OutputFormat::ErrorMessage)
+            showError(str);
+    });
 }
 
 // Workaround for QDS-13763, when UL-10456 is completed this can be removed with the next LTS