AudioSystem: no error log for virtual source conversion to stream

When converting audio attributes to stream type, do not log an
error if no product strategy support USAGE_VIRTUAL_SOURCE.

Bug: 146558301
Test: check logs after using AudioPolicy for injection
Change-Id: I8313b9d27583934e7a64edbfe49d52bad587f372
diff --git a/media/libaudioclient/AudioSystem.cpp b/media/libaudioclient/AudioSystem.cpp
index cb9c7ba..480930b 100644
--- a/media/libaudioclient/AudioSystem.cpp
+++ b/media/libaudioclient/AudioSystem.cpp
@@ -1491,7 +1491,14 @@
             }
         }
     }
-    ALOGE("invalid attributes %s when converting to stream",  toString(attr).c_str());
+    switch (attr.usage) {
+        case AUDIO_USAGE_VIRTUAL_SOURCE:
+            // virtual source is not expected to have an associated product strategy
+            break;
+        default:
+            ALOGE("invalid attributes %s when converting to stream",  toString(attr).c_str());
+            break;
+    }
     return AUDIO_STREAM_MUSIC;
 }