xkb: Provide support for the XF86Phone symbol

Change-Id: I19fd0bc7a56b4baa5b6d40836d5f0401a3b11c49
Reviewed-by: Laszlo Agocs <laszlo.agocs@theqtcompany.com>

src/plugins/platforms/wayland/shared/qwaylandxkb.cpp

@@ -135,6 +135,8 @@ static const uint32_t KeyTbl[] = {
 
     XKB_KEY_XF86Eject,               Qt::Key_Eject,
 
+    XKB_KEY_XF86Phone,               Qt::Key_ToggleCallHangup,
+
     0,                          0
 };