Remove unused import

StructGroupReq is imported but not used.
The import can be removed.

Bug: 113148576
Test: build only
Change-Id: I6b2ec5eb3f6c6e298fcde8e47dfd0979f889ca1d

services/net/java/android/net/ip/RouterAdvertisementDaemon.java

@@ -28,7 +28,6 @@ import android.net.TrafficStats;
 import android.net.util.InterfaceParams;
 import android.system.ErrnoException;
 import android.system.Os;
-import android.system.StructGroupReq;
 import android.system.StructTimeval;
 import android.util.Log;