tty: fix typo in error message
tty: fix typo in error message

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