monitor: Use traditional command interface for HMP device_add

All QMP commands use the "new" handler interface (mhandler.cmd_new).
Most HMP commands still use the traditional interface (mhandler.cmd),
but a few use the "new" one.  Complicates handle_user_command() for no
gain, so I'm converting these to the traditional interface.

For device_add, that's easy: just wrap the obvious hmp_device_add()
around do_device_add().

monitor_user_noop() is now unused, drop it.
Signed-off-by: NMarkus Armbruster <armbru@redhat.com>
Reviewed-by: NEric Blake <eblake@redhat.com>
Reviewed-by: NLuiz Capitulino <lcapitulino@redhat.com>

hmp-commands.hx

@@ -653,8 +653,7 @@ ETEXI
         .args_type  = "device:O",
         .params     = "driver[,prop=value][,...]",
         .help       = "add device, like -device on the command line",
-        .user_print = monitor_user_noop,
-        .mhandler.cmd_new = do_device_add,
+        .mhandler.cmd = hmp_device_add,
         .command_completion = device_add_completion,
     },
 

hmp.c

@@ -22,6 +22,7 @@
 #include "qmp-commands.h"
 #include "qemu/sockets.h"
 #include "monitor/monitor.h"
+#include "monitor/qdev.h"
 #include "qapi/opts-visitor.h"
 #include "qapi/string-output-visitor.h"
 #include "qapi-visit.h"
@@ -1499,6 +1500,11 @@ void hmp_migrate(Monitor *mon, const QDict *qdict)
     }
 }
 
+void hmp_device_add(Monitor *mon, const QDict *qdict)
+{
+    do_device_add(mon, qdict, NULL);
+}
+
 void hmp_device_del(Monitor *mon, const QDict *qdict)
 {
     const char *id = qdict_get_str(qdict, "id");

hmp.h

@@ -80,6 +80,7 @@ void hmp_block_job_pause(Monitor *mon, const QDict *qdict);
 void hmp_block_job_resume(Monitor *mon, const QDict *qdict);
 void hmp_block_job_complete(Monitor *mon, const QDict *qdict);
 void hmp_migrate(Monitor *mon, const QDict *qdict);
+void hmp_device_add(Monitor *mon, const QDict *qdict);
 void hmp_device_del(Monitor *mon, const QDict *qdict);
 void hmp_dump_guest_memory(Monitor *mon, const QDict *qdict);
 void hmp_netdev_add(Monitor *mon, const QDict *qdict);

monitor.c

@@ -378,8 +378,6 @@ static int GCC_FMT_ATTR(2, 3) monitor_fprintf(FILE *stream,
     return 0;
 }
 
-static void monitor_user_noop(Monitor *mon, const QObject *data) { }
-
 static inline int handler_is_qobject(const mon_cmd_t *cmd)
 {
     return cmd->user_print != NULL;