Add a log tag

Change-Id: If30aa8536130cf6ff9918ce97c5e4e8651ae2fef
diff --git a/libs/utils/Trace.cpp b/libs/utils/Trace.cpp
index d532296..f7d8abe 100644
--- a/libs/utils/Trace.cpp
+++ b/libs/utils/Trace.cpp
@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+#define LOG_TAG "Trace"
+
 #include <cutils/properties.h>
 #include <utils/Log.h>
 #include <utils/Trace.h>