autotest: Add volteer to list of hotword and echo_ref

BUG=b:183582307
TEST=run audio_InternalCardNodes.unplug on chromeos15-audiobox14-host2

Change-Id: I484ce85739fd61b97b591ba555acf4a50e270b04
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/third_party/autotest/+/2784280
Tested-by: En-Shuo Hsu <enshuo@chromium.org>
Auto-Submit: En-Shuo Hsu <enshuo@chromium.org>
Commit-Queue: Kalin Stoyanov <kalin@chromium.org>
Reviewed-by: Kalin Stoyanov <kalin@chromium.org>
diff --git a/client/cros/audio/audio_spec.py b/client/cros/audio/audio_spec.py
index 5b41d36..c3511ba 100644
--- a/client/cros/audio/audio_spec.py
+++ b/client/cros/audio/audio_spec.py
@@ -70,7 +70,7 @@
 
 BOARDS_WITH_HOTWORDING = [
         'atlas', 'coral', 'eve', 'kevin', 'nami', 'nocturne', 'pyro', 'rammus',
-        'samus'
+        'samus', 'volteer'
 ]
 
 
@@ -95,7 +95,7 @@
 
     """
     board_name = strip_kernelnext_suffix(board_name)
-    return board_name in ['nocturne', 'atlas']
+    return board_name in ['nocturne', 'atlas', 'volteer']
 
 
 BoardInfo = collections.namedtuple('BoardInfo', ['board', 'model', 'sku'])