When running with the RPi backend, Weston sefaults during shutdown. This is
due to the fact that `compositor->backend` is never initialised, and there
is no NULL check prior to calling `destroy()`.
This commit fixes the issue by making `rpi_backend_create()` intialise
`compositor->backend` - just like the X11 backend does.
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=91886
Signed-off-by: John Sadler <deathofathousandpapercuts@gmail.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
John Sadler
7628789640