timeutil: correct position of doxygen end-group comment

swap the relative position of the __cplusplus closing
bracket and the doxygen end-group comment.

Signed-off-by: Chris Friedt <[email protected]>

Author: cfriedt

include/zephyr/sys/timeutil.h

@@ -301,12 +301,12 @@ int timeutil_sync_local_from_ref(const struct timeutil_sync_state *tsp,
  */
 int32_t timeutil_sync_skew_to_ppb(float skew);
 
-#ifdef __cplusplus
-}
-#endif
-
 /**
  * @}
  */
 
+#ifdef __cplusplus
+}
+#endif
+
 #endif /* ZEPHYR_INCLUDE_SYS_TIMEUTIL_H_ */