ProjectExplorer: Make Device::displayType a data member

Change-Id: If650f660e3b10bc28d575ded07a854f59be26f87
Reviewed-by: Christian Kandeler <christian.kandeler@qt.io>

src/plugins/qnx/qnxdevice.cpp

@@ -82,17 +82,13 @@ class QnxPortsGatheringMethod : public PortsGatheringMethod
 
 QnxDevice::QnxDevice()
 {
+    setDisplayType(tr("QNX"));
     addDeviceAction({tr("Deploy Qt libraries..."), [](const IDevice::Ptr &device, QWidget *parent) {
         QnxDeployQtLibrariesDialog dialog(device, parent);
         dialog.exec();
     }});
 }
 
-QString QnxDevice::displayType() const
-{
-    return tr("QNX");
-}
-
 OsType QnxDevice::osType() const
 {
     return OsTypeOtherUnix;