BpfUtils.java - add requires T+ annotation

Networking bpf (including cgroup related portions)
was mainlined in Android T.

Test: TreeHugger
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: I779584828f03caa2d61d5081cb3d39566db9b9de

staticlibs/device/com/android/net/module/util/BpfUtils.java

@@ -15,7 +15,10 @@
  */
 package com.android.net.module.util;
 
+import android.os.Build;
+
 import androidx.annotation.NonNull;
+import androidx.annotation.RequiresApi;
 
 import java.io.IOException;
 
@@ -24,6 +27,7 @@ import java.io.IOException;
  *
  * {@hide}
  */
+@RequiresApi(Build.VERSION_CODES.TIRAMISU)
 public class BpfUtils {
     static {
         System.loadLibrary(JniUtil.getJniLibraryName(BpfUtils.class.getPackage()));