hmp: Add "calc_dirty_rate" and "info dirty_rate" cmds

These two commands are missing when adding the QMP sister commands.
Add them, so developers can play with them easier.

Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
Message-Id: <4cc0039fc3ad6145136770cf3b0f056c09a2910b.1623027729.git.huangy81@chinatelecom.cn>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
diff --git a/hmp-commands-info.hx b/hmp-commands-info.hx
index b2347a6..fb59c27 100644
--- a/hmp-commands-info.hx
+++ b/hmp-commands-info.hx
@@ -867,3 +867,16 @@
   ``info replay``
     Display the record/replay information: mode and the current icount.
 ERST
+
+    {
+        .name       = "dirty_rate",
+        .args_type  = "",
+        .params     = "",
+        .help       = "show dirty rate information",
+        .cmd        = hmp_info_dirty_rate,
+    },
+
+SRST
+  ``info dirty_rate``
+    Display the vcpu dirty rate information.
+ERST