Replacing defined time functions with standard because cpp17

Signed-off-by: Milo Lin <100027790@mvla.net>
Change-Id: Ia84519fb0d4ef141654e2f29d59b38ec1e48cfc2
diff --git a/aos/time/time.cc b/aos/time/time.cc
index 0a633ef..882f925 100644
--- a/aos/time/time.cc
+++ b/aos/time/time.cc
@@ -221,7 +221,7 @@
   using systick_duration =
       std::chrono::duration<uint32_t, std::ratio<1, F_CPU>>;
 
-  return time_point(aos::time::round<std::chrono::nanoseconds>(
+  return time_point(std::chrono::round<std::chrono::nanoseconds>(
       std::chrono::milliseconds(ms_count) + systick_duration(counter_up)));
 
 #endif  // __linux__