fullscreen: Remove dirty sizing trick
fullscreen: Remove dirty sizing trick

xdg-shell mandates that the FULLSCREEN state means that we must match
the size that we were configured to, at least by default. Other states
or protocol extensions might relax this requirement, but at least for
now implement the behavior specified in the protocol documentation.

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