audio: Add device definitions for Echo Reference

This enum exists in AudioSystem, adding to AudioDeviceInfo.

Bug: 178379355
Test: Build and flash on Yukawa device.
Change-Id: I4a4aade913c0823a20a538cb740b2a83f775415c
diff --git a/services/audiopolicy/managerdefault/AudioPolicyManager.cpp b/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
index e721a78..6ef815d 100644
--- a/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
+++ b/services/audiopolicy/managerdefault/AudioPolicyManager.cpp
@@ -2183,7 +2183,9 @@
             status = BAD_VALUE;
             goto error;
         }
-        if (policyMix) {
+        if (device->type() == AUDIO_DEVICE_IN_ECHO_REFERENCE) {
+            *inputType = API_INPUT_MIX_CAPTURE;
+        } else if (policyMix) {
             ALOG_ASSERT(policyMix->mMixType == MIX_TYPE_RECORDERS, "Invalid Mix Type");
             // there is an external policy, but this input is attached to a mix of recorders,
             // meaning it receives audio injected into the framework, so the recorder doesn't