Fix C++23 build.

libc++ has cleaned up transitive dependencies (but only for C++23).

Change-Id: I88a03ebaf03b904e85bbfa85deff79405ccb97bc
diff --git a/transport/HidlLazyUtils.cpp b/transport/HidlLazyUtils.cpp
index c5f8c74..618f279 100644
--- a/transport/HidlLazyUtils.cpp
+++ b/transport/HidlLazyUtils.cpp
@@ -16,6 +16,8 @@
 
 #define LOG_TAG "HidlLazyUtils"
 
+#include <mutex>
+
 #include <hidl/HidlLazyUtils.h>
 #include <hidl/HidlTransportSupport.h>