Looper: Fixed compile error when enabling DEBUG_CALLBACKS

When enabling DEBUG_CALLBACKS , compiler complains
for the undeclared identifier 'fd'.
Fix by removing undeclared objects.

Change-Id: I751a9ef9d8843350105acd6a30645f897050ffa4

libutils/Android.bp

@@ -203,6 +203,7 @@ cc_library {
     defaults: ["libutils_impl_defaults"],
 
     cflags: [
+        "-DDEBUG_CALLBACKS=1",
         "-DDEBUG_POLL_AND_WAKE=1",
         "-DDEBUG_REFS=1",
         "-DDEBUG_TOKENIZER=1",

libutils/Looper.cpp

@@ -534,7 +534,7 @@ int Looper::removeFd(int fd) {
 
 int Looper::removeSequenceNumberLocked(SequenceNumber seq) {
 #if DEBUG_CALLBACKS
-    ALOGD("%p ~ removeFd - fd=%d, seq=%u", this, fd, seq);
+    ALOGD("%p ~ removeFd - seq=%" PRIu64, this, seq);
 #endif
 
     const auto& request_it = mRequests.find(seq);