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-drm.c b/src/compositor-drm.c
index 893877d..39d061b 100644
--- a/src/compositor-drm.c
+++ b/src/compositor-drm.c
@@ -3121,7 +3121,8 @@
 	create_sprites(b);
 
 	if (udev_input_init(&b->input,
-			    compositor, b->udev, seat_id) < 0) {
+			    compositor, b->udev, seat_id,
+			    config->configure_device) < 0) {
 		weston_log("failed to create input devices\n");
 		goto err_sprite;
 	}