libinput: don't use weston_config when configuring input devices

Instead add callbacks to the drm and fbdev backends and pass that to
the input backens so that when a new device needs to be configured
that is called and the compositor can configure it.

Signed-off-by: Giulio Camuffo <giuliocamuffo@gmail.com>
Reviewed-by: Quentin Glidic <sardemff7+git@sardemff7.net>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
diff --git a/src/compositor-fbdev.c b/src/compositor-fbdev.c
index ee762e3..f66fe47 100644
--- a/src/compositor-fbdev.c
+++ b/src/compositor-fbdev.c
@@ -797,7 +797,8 @@
 	if (fbdev_output_create(backend, param->device) < 0)
 		goto out_launcher;
 
-	udev_input_init(&backend->input, compositor, backend->udev, seat_id);
+	udev_input_init(&backend->input, compositor, backend->udev,
+			seat_id, param->configure_device);
 
 	compositor->backend = &backend->base;
 	return backend;