audio policy: add new input audio device

Add entry for AUDIO_DEVICE_IN_LOOPBACK to string to enum table.

Bug: 15437484
Change-Id: I552df0969c745bdf66ff9e5d7bd864ef9e3f438d
diff --git a/services/audiopolicy/AudioPolicyManager.cpp b/services/audiopolicy/AudioPolicyManager.cpp
index d4c9374..9708d0f 100644
--- a/services/audiopolicy/AudioPolicyManager.cpp
+++ b/services/audiopolicy/AudioPolicyManager.cpp
@@ -101,6 +101,7 @@
     STRING_TO_ENUM(AUDIO_DEVICE_IN_LINE),
     STRING_TO_ENUM(AUDIO_DEVICE_IN_SPDIF),
     STRING_TO_ENUM(AUDIO_DEVICE_IN_BLUETOOTH_A2DP),
+    STRING_TO_ENUM(AUDIO_DEVICE_IN_LOOPBACK),
 };
 
 const StringToEnum sFlagNameToEnumTable[] = {