Nest some more namespaces

Did someone previously suggest that all namespace had been
nested?  Silly.

Signed-off-by: Stephan Pleines <pleines.stephan@gmail.com>
Change-Id: I22278c1caaeba8b47dc46fb2ed3078c20a11e190
diff --git a/aos/ipc_lib/lockless_queue_stepping.h b/aos/ipc_lib/lockless_queue_stepping.h
index 7aab193..590534f 100644
--- a/aos/ipc_lib/lockless_queue_stepping.h
+++ b/aos/ipc_lib/lockless_queue_stepping.h
@@ -7,9 +7,7 @@
 #include "aos/ipc_lib/lockless_queue.h"
 #include "aos/ipc_lib/lockless_queue_memory.h"
 
-namespace aos {
-namespace ipc_lib {
-namespace testing {
+namespace aos::ipc_lib::testing {
 
 #if defined(__ARM_EABI__)
 // There are various reasons why we might not actually be able to do this
@@ -142,8 +140,6 @@
 
 #endif
 
-}  // namespace testing
-}  // namespace ipc_lib
-}  // namespace aos
+}  // namespace aos::ipc_lib::testing
 
 #endif  // AOS_IPC_LIB_LOCKLESS_QUEUE_STEPPING_H_