chardev: add hmp hotplug commands

Add chardev-add and chardev-remove commands to the human monitor.
chardev-add accepts the same syntax as -chardev, chardev-remove
expects a chardev id.

Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

hmp-commands.hx

@@ -1482,6 +1482,38 @@ Password is invalidated at the given time.  @var{nsec} are the seconds
 passed since 1970, i.e. unix epoch.
 
 @end table
+ETEXI
+
+    {
+        .name       = "chardev-add",
+        .args_type  = "args:s",
+        .params     = "args",
+        .help       = "add chardev",
+        .mhandler.cmd = hmp_chardev_add,
+    },
+
+STEXI
+@item chardev_add args
+@findex chardev_add
+
+chardev_add accepts the same parameters as the -chardev command line switch.
+
+ETEXI
+
+    {
+        .name       = "chardev-remove",
+        .args_type  = "id:s",
+        .params     = "id",
+        .help       = "remove chardev",
+        .mhandler.cmd = hmp_chardev_remove,
+    },
+
+STEXI
+@item chardev_remove id
+@findex chardev_remove
+
+Removes the chardev @var{id}.
+
 ETEXI
 
     {