wayland-egl: Force roundtrips to get device name and authenticate correctly

wayland-egl: Force roundtrips to get device name and authenticate correctly

If the client hasn't done the initial wl_display_iterate() at the time
we initialize the display, we have to do that in platform_wayland.c.
Make sure we detect that correctly instead of dup()ing fd=0, and use
the sync callback to make sure we don't wait forever for authorization that
won't happen.