Avoid using FileDescriptor#getInt$() on R

FileDescriptor#getInt$() is a hidden API with the unsupportedApiUsage
annotation on R. Accessing it will cause a NewApi linter check error.
It should be removed from OffloadHalHidlImpl as it is only used for
log messages.

Bug: b/205762647
Test: m
Change-Id: Ie41d12988aee65a066dfb1529e828f4523cc0907
diff --git a/Tethering/src/com/android/networkstack/tethering/OffloadHalHidlImpl.java b/Tethering/src/com/android/networkstack/tethering/OffloadHalHidlImpl.java
index e0a9878..71922f9 100644
--- a/Tethering/src/com/android/networkstack/tethering/OffloadHalHidlImpl.java
+++ b/Tethering/src/com/android/networkstack/tethering/OffloadHalHidlImpl.java
@@ -74,10 +74,7 @@
      */
     public boolean initOffload(@NonNull NativeHandle handle1, @NonNull NativeHandle handle2,
             @NonNull OffloadHalCallback callback) {
-        final String logmsg = String.format("initOffload(%d, %d, %s)",
-                handle1.getFileDescriptor().getInt$(), handle2.getFileDescriptor().getInt$(),
-                (callback == null) ? "null"
-                : "0x" + Integer.toHexString(System.identityHashCode(callback)));
+        final String logmsg = "initOffload()";
 
         mOffloadHalCallback = callback;
         mTetheringOffloadCallback = new TetheringOffloadCallback(