drm/udl: Fix potential URB leaks

A couple of error handlings forgot to process the URB completion.
Those are both with WARN_ON() so should be visible, but we must fix
them in anyway.

Fixes: 7350b2a3 ("drm/udl: Replace BUG_ON() with WARN_ON()")
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20220908095115.23396-10-tiwai@suse.de