ALSA: hda: beep: Drop stale mutex

The beep->mutex is no longer used since the drop of beep_mode=2.
Let's get rid of it.

Fixes: 0920c9b4 ("ALSA: hda - Remove beep_mode=2")
Link: https://lore.kernel.org/r/20240222153148.19691-1-tiwai@suse.deSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/hda_beep.c

@@ -231,7 +231,6 @@ int snd_hda_attach_beep_device(struct hda_codec *codec, int nid)
 	codec->beep = beep;
 
 	INIT_WORK(&beep->beep_work, &snd_hda_generate_beep);
-	mutex_init(&beep->mutex);
 
 	input_dev = input_allocate_device();
 	if (!input_dev) {

sound/pci/hda/hda_beep.h

@@ -27,7 +27,6 @@ struct hda_beep {
 	unsigned int playing:1;
 	unsigned int keep_power_at_enable:1;	/* set by driver */
 	struct work_struct beep_work; /* scheduled task for beep event */
-	struct mutex mutex;
 	void (*power_hook)(struct hda_beep *beep, bool on);
 };