ALSA: hda - Fix build errors with CONFIG_SND_HDA_INPUT_BEEP=n

Disable beep-related codes when CONFIG_SND_HDA_INPUT_BEEP isn't set.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c
index e344235..2be61b3 100644
--- a/sound/pci/hda/hda_codec.c
+++ b/sound/pci/hda/hda_codec.c
@@ -1959,6 +1959,7 @@
 }
 EXPORT_SYMBOL_HDA(snd_hda_mixer_amp_switch_put);
 
+#ifdef CONFIG_SND_HDA_INPUT_BEEP
 /**
  * snd_hda_mixer_amp_switch_put_beep - Put callback for a beep AMP switch
  *
@@ -1975,6 +1976,7 @@
 	return snd_hda_mixer_amp_switch_put(kcontrol, ucontrol);
 }
 EXPORT_SYMBOL_HDA(snd_hda_mixer_amp_switch_put_beep);
+#endif /* CONFIG_SND_HDA_INPUT_BEEP */
 
 /*
  * bound volume controls