hal: add echo reference for headset

Set headphone echo reference for headset.

Change-Id: Ia94b6a28a61e44c4391f41fb4f8c565c9a7128e0
diff --git a/hal/msm8974/platform.c b/hal/msm8974/platform.c
index 995ad6d..56ac059 100644
--- a/hal/msm8974/platform.c
+++ b/hal/msm8974/platform.c
@@ -1905,7 +1905,8 @@
         else if (compare_device_type(out_devices, AUDIO_DEVICE_OUT_EARPIECE))
             strlcat(ec_ref_mixer_path, " handset",
                     MIXER_PATH_MAX_LENGTH);
-        else if (compare_device_type(out_devices, AUDIO_DEVICE_OUT_WIRED_HEADPHONE))
+        else if (compare_device_type(out_devices, AUDIO_DEVICE_OUT_WIRED_HEADPHONE) ||
+                 compare_device_type(out_devices, AUDIO_DEVICE_OUT_WIRED_HEADSET))
             strlcat(ec_ref_mixer_path, " headphones",
                     MIXER_PATH_MAX_LENGTH);
         else if (compare_device_type(out_devices, AUDIO_DEVICE_OUT_USB_HEADSET))