ALSA: hda - Fix NULL dereference with enable_beep=0 option

Signed-off-by: Takashi Iwai <tiwai@suse.de>

sound/pci/hda/patch_sigmatel.c

@@ -3779,17 +3779,18 @@ static int stac92xx_parse_auto_config(struct hda_codec *codec, hda_nid_t dig_out
 		err = snd_hda_attach_beep_device(codec, nid);
 		if (err < 0)
 			return err;
+		if (codec->beep) {
 			/* IDT/STAC codecs have linear beep tone parameter */
 			codec->beep->linear_tone = 1;
 			/* if no beep switch is available, make its own one */
 			caps = query_amp_caps(codec, nid, HDA_OUTPUT);
-		if (codec->beep &&
-		    !((caps & AC_AMPCAP_MUTE) >> AC_AMPCAP_MUTE_SHIFT)) {
+			if (!(caps & AC_AMPCAP_MUTE)) {
 				err = stac92xx_beep_switch_ctl(codec);
 				if (err < 0)
 					return err;
 			}
 		}
+	}
 #endif
 
 	err = stac92xx_auto_create_hp_ctls(codec, &spec->autocfg);