Modify unexpected mtu debug message to print mtu

Change-Id: Iacc78582c5e3d6b156e8e2eda25e89e0e5be6eda
diff --git a/services/core/java/com/android/server/ConnectivityService.java b/services/core/java/com/android/server/ConnectivityService.java
index ba08a2e..b56923f 100644
--- a/services/core/java/com/android/server/ConnectivityService.java
+++ b/services/core/java/com/android/server/ConnectivityService.java
@@ -2632,7 +2632,7 @@
        final int mtu = nt.getLinkProperties().getMtu();
 
        if (mtu < 68 || mtu > 10000) {
-           loge("Unexpected mtu value: " + nt);
+           loge("Unexpected mtu value: " + mtu + ", " + nt);
            return;
        }