monitor: Move qmp_query_qmp_schema to qmp-cmds-control.c

monitor/misc.c contains code that works only in the system emulator, so
it can't be linked to tools like a storage daemon. In order to make
schema introspection available for tools, move the function to
monitor/qmp-cmds-control.c, which can be linked into the storage daemon.

Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-Id: <20200129102239.31435-5-kwolf@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
diff --git a/monitor/monitor-internal.h b/monitor/monitor-internal.h
index 4d402de..3e6baba 100644
--- a/monitor/monitor-internal.h
+++ b/monitor/monitor-internal.h
@@ -180,4 +180,7 @@
 void handle_hmp_command(MonitorHMP *mon, const char *cmdline);
 int hmp_compare_cmd(const char *name, const char *list);
 
+void qmp_query_qmp_schema(QDict *qdict, QObject **ret_data,
+                                 Error **errp);
+
 #endif