Fix xdg-output creation

In 1a11abc821 some function calls in the createXdgOutput function were
accidentally removed resulting in possibility of broken setup on startup.

Add these calls back again.

abstract_wayland_output.cpp

@@ -171,6 +171,9 @@ void AbstractWaylandOutput::createXdgOutput()
         return;
     }
     m_xdgOutput = waylandServer()->xdgOutputManager()->createXdgOutput(m_waylandOutput, m_waylandOutput);
+    m_xdgOutput->setLogicalSize(pixelSize() / scale());
+    m_xdgOutput->setLogicalPosition(m_globalPos);
+    m_xdgOutput->done();
 }
 
 void AbstractWaylandOutput::initWaylandOutput()