compositor: remove unused *_uniform members
compositor: remove unused *_uniform members

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

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