fix log_displayer -N

Change-Id: Ifcfacf628d8fd62e0469dccfb8e9fa1af81d9a05
diff --git a/aos/linux_code/logging/log_displayer.cc b/aos/linux_code/logging/log_displayer.cc
index cdc8f46..4050bd4 100644
--- a/aos/linux_code/logging/log_displayer.cc
+++ b/aos/linux_code/logging/log_displayer.cc
@@ -147,7 +147,7 @@
     };
     int option_index = 0;
 
-    const int c = getopt_long(argc, argv, "n:l:p:fts:m:o:h",
+    const int c = getopt_long(argc, argv, "N:n:l:p:fts:m:o:h",
                     long_options, &option_index);
     if (c == -1) { // if we're at the end
       break;