ALSA: hda_intel: Digital PC Beep - delay input device unregistration

The massive register/unregister calls for input device layer might be
overkill. Delay unregister call by one HZ as workaround.

Also, as benefit, beep->enabled variable is changed immediately now
(not from workqueue).

Signed-off-by: Jaroslav Kysela <perex@perex.cz>
Signed-off-by: Takashi Iwai <tiwai@suse.de>