ALSA: hda/conexant: Mute speakers at suspend / shutdown

Use the new helper to mute speakers at suspend / shutdown for avoiding
click noises.

Link: https://bugzilla.suse.com/show_bug.cgi?id=1228269
Link: https://patch.msgid.link/20240726142625.2460-2-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>