MTP: replace printfs with logcat

Change-Id: I2c30921098e2dc049dc5fc1e0a548ead33c363e0
Signed-off-by: Mike Lockwood <lockwood@android.com>
diff --git a/media/mtp/MtpStringBuffer.cpp b/media/mtp/MtpStringBuffer.cpp
index 8694575..2d3cf69 100644
--- a/media/mtp/MtpStringBuffer.cpp
+++ b/media/mtp/MtpStringBuffer.cpp
@@ -14,6 +14,8 @@
  * limitations under the License.
  */
 
+#define LOG_TAG "MtpStringBuffer"
+
 #include <string.h>
 
 #include "MtpDataPacket.h"