wayland-egl: Drop ill-defined pixmap support
wayland-egl: Drop ill-defined pixmap support

We don't have a use case for this and the actual semantics and
synchronization behavior of wl_egl_pixmap were never really well-defined.
It also doesn't provide the cross-process buffer sharing that make
window systems pixmaps useful in other window systems.

abooij/wayland,eyolfson/wayland,tulcod/wayland,tulcod/wayland,sir-murray/wayland,mchalupa/wayland,bitfactor/wayland,abooij/wayland,bitfactor/wayland,mchalupa/wayland,abooij/wayland,eyolfson/wayland,eyolfson/wayland,sir-murray/wayland,mchalupa/wayland,tulcod/wayland,bitfactor/wayland,sir-murray/wayland