hmp: Allow help on preconfig commands

Allow the 'help' command in preconfig state but
make it only list the preconfig commands.

Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Message-Id: <20180620153947.30834-3-dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
diff --git a/hmp-commands.hx b/hmp-commands.hx
index 754620e..7ce991f 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -15,6 +15,7 @@
         .params     = "[cmd]",
         .help       = "show the help",
         .cmd        = do_help_cmd,
+        .flags      = "p",
     },
 
 STEXI