[ALSA] hda-codec - add snd_hda_codec_stereo() function

Added snd_hda_codec_amp_stereo() function that changes both of stereo
channels with the same mask and value bits.  It simplifies most of
amp-handling codes.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Jaroslav Kysela <perex@suse.cz>
diff --git a/sound/pci/hda/hda_generic.c b/sound/pci/hda/hda_generic.c
index d5f11801..91cd9b9 100644
--- a/sound/pci/hda/hda_generic.c
+++ b/sound/pci/hda/hda_generic.c
@@ -218,8 +218,7 @@
 	ofs = (node->amp_out_caps & AC_AMPCAP_OFFSET) >> AC_AMPCAP_OFFSET_SHIFT;
 	if (val >= ofs)
 		val -= ofs;
-	snd_hda_codec_amp_update(codec, node->nid, 0, HDA_OUTPUT, 0, 0xff, val);
-	snd_hda_codec_amp_update(codec, node->nid, 0, HDA_OUTPUT, 1, 0xff, val);
+	snd_hda_codec_amp_stereo(codec, node->nid, HDA_OUTPUT, 0, 0xff, val);
 	return 0;
 }
 
@@ -234,10 +233,7 @@
 	ofs = (node->amp_in_caps & AC_AMPCAP_OFFSET) >> AC_AMPCAP_OFFSET_SHIFT;
 	if (val >= ofs)
 		val -= ofs;
-	snd_hda_codec_amp_update(codec, node->nid, 0, HDA_INPUT, index,
-				 0xff, val);
-	snd_hda_codec_amp_update(codec, node->nid, 1, HDA_INPUT, index,
-				 0xff, val);
+	snd_hda_codec_amp_stereo(codec, node->nid, HDA_INPUT, index, 0xff, val);
 	return 0;
 }