window: simplify window_create_surface
window: simplify window_create_surface

Signed-off-by: Pekka Paalanen <6c0263d81461c956d504307112a4ce25eaacc3d1@gmail.com>

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