Add missing libc++ includes

Bug: 175635923
Test: m MODULES-IN-hardware-interfaces-wifi
Change-Id: Icfaa316bb50b680a2c03c3d818f6ae01860dd334
diff --git a/wifi/netlinkinterceptor/aidl/default/InterceptorRelay.h b/wifi/netlinkinterceptor/aidl/default/InterceptorRelay.h
index 0178c90..915b5ff 100644
--- a/wifi/netlinkinterceptor/aidl/default/InterceptorRelay.h
+++ b/wifi/netlinkinterceptor/aidl/default/InterceptorRelay.h
@@ -18,6 +18,7 @@
 
 #include <libnl++/Socket.h>
 
+#include <atomic>
 #include <mutex>
 #include <thread>