xwm: Fix configure notify handler
xwm: Fix configure notify handler

We only get configure notify for toplevel (frame or override-redirect window)
and those are the cases where we want to update window->x/y.  The way the
code worked, we'd exit immeidately in those cases and window->x/y would
not be updated.

Gnurou/weston,Fantu/compositor-spice,Tarnyko/weston-xdg_surface_present,jonnylamb/weston,Gnurou/weston,giucam/weston,eyolfson/weston,udoprog/weston,kwm81/weston,Fantu/compositor-spice,sir-murray/weston,mchalupa/weston,eyolfson/weston,krezovic/weston,mchalupa/weston,kwm81/weston,krezovic/weston,xorgy/weston,jonnylamb/weston,xorgy/weston,giucam/weston,udoprog/weston,Fantu/compositor-spice,Tarnyko/weston-xdg_surface_present,sir-murray/weston