monitor: Add chardev-add backend argument completion.

Signed-off-by: Hani Benhabiles <hani@linux.com>
Signed-off-by: Luiz Capitulino <lcapitulino@redhat.com>
diff --git a/hmp.h b/hmp.h
index affc2b6..f8e16a8 100644
--- a/hmp.h
+++ b/hmp.h
@@ -99,5 +99,6 @@
 void device_del_completion(ReadLineState *rs, int nb_args, const char *str);
 void sendkey_completion(ReadLineState *rs, int nb_args, const char *str);
 void chardev_remove_completion(ReadLineState *rs, int nb_args, const char *str);
+void chardev_add_completion(ReadLineState *rs, int nb_args, const char *str);
 
 #endif