ART: Move to using locks.h instead of mutex.h

When only annotating lock requirements, use locks.h.

Bug: 119869270
Test: mmma art
Change-Id: I1608b03254712feff0072ebad012c3af0cc3dda4
diff --git a/runtime/gc/reference_queue.cc b/runtime/gc/reference_queue.cc
index 5c11e50..95871da 100644
--- a/runtime/gc/reference_queue.cc
+++ b/runtime/gc/reference_queue.cc
@@ -17,6 +17,7 @@
 #include "reference_queue.h"
 
 #include "accounting/card_table-inl.h"
+#include "base/mutex.h"
 #include "collector/concurrent_copying.h"
 #include "heap.h"
 #include "mirror/class-inl.h"