ALSA: fireworks: fix asymmetric API call at unit removal

ALSA fireworks driver has a bug not to call an API to destroy
'cmp_connection' structure for input direction. Currently this causes no
issues because it just destroys 'mutex' structure, while it's better to
fix it for future work.

Fix: d23c2cc4

 ("ALSA: fireworks/bebob/dice/oxfw: allow stream destructor after releasing runtime")
Signed-off-by: Takashi Sakamoto <o-takashi@sakamocchi.jp>
Signed-off-by: Takashi Iwai <tiwai@suse.de>