drm/udl: Move connector to modesetting code

Move the connector next to the rest of the modesetting code. No
functional changes.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221006095355.23579-6-tzimmermann@suse.de