Rotation: Fix 90 and 270 degree screen rotation

Now the applications are also centered correctly at 90 and 270 degrees
rotation.

BCS 746-000787

qml/Screen.qml

@@ -74,9 +74,10 @@ WaylandOutput {
 
         WaylandMouseTracker {
             id: mouseTracker
-            anchors.fill: parent
+            anchors.centerIn: parent
             windowSystemCursorEnabled: true
-            rotation: 0
+            width: (rotation==90 || rotation==270) ? parent.height : parent.width
+            height: (rotation==90 || rotation==270) ? parent.width : parent.height
 
             Rectangle {
                 anchors.fill: parent