xwl: dont mark the even source as readable

wl_event_source_check makes the event trigger until onx11event returns non
zero. but we arent removing the event source from the event loop so lets
not mark it at all and recieve spurious constant calls.

src/xwayland/XWM.cpp

@@ -961,7 +961,6 @@ CXWM::CXWM() : m_connection(makeUnique<CXCBConnection>(g_pXWayland->m_server->m_
     m_screen                              = screen_iterator.data;
 
     m_eventSource = wl_event_loop_add_fd(g_pCompositor->m_wlEventLoop, g_pXWayland->m_server->m_xwmFDs[0].get(), WL_EVENT_READABLE, ::onX11Event, nullptr);
-    wl_event_source_check(m_eventSource);
 
     gatherResources();
     getVisual();