shm: Check width, height and stride for invalid values
shm: Check width, height and stride for invalid values

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