ALSA: cmipci: Implement channel mapping

Simply enable the channel map according to the h/w capability.

Signed-off-by: Takashi Iwai <tiwai@suse.de>
diff --git a/sound/pci/cmipci.c b/sound/pci/cmipci.c
index 7c25906..22122ff 100644
--- a/sound/pci/cmipci.c
+++ b/sound/pci/cmipci.c
@@ -1962,6 +1962,12 @@
 	snd_pcm_lib_preallocate_pages_for_all(pcm, SNDRV_DMA_TYPE_DEV,
 					      snd_dma_pci_data(cm->pci), 64*1024, 128*1024);
 
+	err = snd_pcm_add_chmap_ctls(pcm, SNDRV_PCM_STREAM_PLAYBACK,
+				     snd_pcm_alt_chmaps, cm->max_channels, 0,
+				     NULL);
+	if (err < 0)
+		return err;
+
 	return 0;
 }