audio: add digital dock (SPDIF) support

This change also supports simultaneous SPDIF and internal
audio, if requested.

Change-Id: Ia9e17b0f6a6fa1fe55afbfbec33df53042cbbb46
diff --git a/audio_policy.conf b/audio_policy.conf
index ec515cb..944d885 100644
--- a/audio_policy.conf
+++ b/audio_policy.conf
@@ -26,7 +26,7 @@
         sampling_rates 44100
         channel_masks AUDIO_CHANNEL_OUT_STEREO
         formats AUDIO_FORMAT_PCM_16_BIT
-        devices AUDIO_DEVICE_OUT_SPEAKER|AUDIO_DEVICE_OUT_WIRED_HEADSET|AUDIO_DEVICE_OUT_WIRED_HEADPHONE|AUDIO_DEVICE_OUT_ALL_SCO|AUDIO_DEVICE_OUT_AUX_DIGITAL
+        devices AUDIO_DEVICE_OUT_SPEAKER|AUDIO_DEVICE_OUT_WIRED_HEADSET|AUDIO_DEVICE_OUT_WIRED_HEADPHONE|AUDIO_DEVICE_OUT_ALL_SCO|AUDIO_DEVICE_OUT_AUX_DIGITAL|AUDIO_DEVICE_OUT_DGTL_DOCK_HEADSET
         flags AUDIO_OUTPUT_FLAG_PRIMARY
       }
     }