hal: Add USB 6ch recording support

Add USB 6 channel MIC device support to enable audio
recording over 6 channels from USB device.

Change-Id: Ice68b6901991266e331cbf7735e187a7d3ed38b3
diff --git a/hal/msm8974/platform.h b/hal/msm8974/platform.h
index e4b925e..6fdb499 100644
--- a/hal/msm8974/platform.h
+++ b/hal/msm8974/platform.h
@@ -204,6 +204,10 @@
     SND_DEVICE_IN_VOICE_USB_HEADSET_MIC,
     SND_DEVICE_IN_UNPROCESSED_USB_HEADSET_MIC,
     SND_DEVICE_IN_VOICE_RECOG_USB_HEADSET_MIC,
+    SND_DEVICE_IN_USB_HEADSET_MULTI_CHANNEL_MIC,
+    SND_DEVICE_IN_USB_HEADSET_MULTI_CHANNEL_MIC_AEC,
+    SND_DEVICE_IN_UNPROCESSED_USB_HEADSET_MULTI_CHANNEL_MIC,
+    SND_DEVICE_IN_VOICE_RECOG_USB_HEADSET_MULTI_CHANNEL_MIC,
     SND_DEVICE_IN_CAPTURE_FM,
     SND_DEVICE_IN_AANC_HANDSET_MIC,
     SND_DEVICE_IN_QUAD_MIC,