ALSA: hda - Always check array bounds in alc_get_line_out_pfx

commit 71aa5ebe upstream.

Even when CONFIG_SND_DEBUG is not enabled, we don't want to
return an arbitrary memory location when the channel count is
larger than we expected.
Signed-off-by: David Henningsson <david.henningsson@canonical.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

sound/pci/hda/patch_realtek.c

@@ -2665,8 +2665,10 @@ static const char *alc_get_line_out_pfx(struct alc_spec *spec, int ch,
 			return "PCM";
 		break;
 	}
-	if (snd_BUG_ON(ch >= ARRAY_SIZE(channel_name)))
+	if (ch >= ARRAY_SIZE(channel_name)) {
+		snd_BUG();
 		return "PCM";
+	}
 
 	return channel_name[ch];
 }