In devices such as ARM boards there could be no input devices connected on
startup, leading to a crash when we try to process artificial events that
could be queued (as gnome-shell does when syncing pointer).
Those events still should refer to a device and, in case we don't have one
provided by libinput we should still return the core devices defined in the
main seat.
(cherry picked from commit 3e85ac8131fc76312a2382d83df6926b88a37415)
2a6782dc10