store the hw addr in the extraInfo field of ethernet NetworkInfos

Change-Id: Ic645396e81d1481d84061945eb9721f0eeb151eb

core/java/android/net/NetworkInfo.java

@@ -345,6 +345,18 @@ public class NetworkInfo implements Parcelable {
         }
     }
 
+    /**
+     * Set the extraInfo field.
+     * @param extraInfo an optional {@code String} providing addditional network state
+     * information passed up from the lower networking layers.
+     * @hide
+     */
+    public void setExtraInfo(String extraInfo) {
+        synchronized (this) {
+            this.mExtraInfo = extraInfo;
+        }
+    }
+
     /**
      * Report the reason an attempt to establish connectivity failed,
      * if one is available.