hw/nvme: mark nvme-subsys non-hotpluggable

We currently lack the infrastructure to handle subsystem hotplugging, so
disable it.

Reviewed-by: Hannes Reinecke <hare@suse.de>
Signed-off-by: Klaus Jensen <k.jensen@samsung.com>
diff --git a/hw/nvme/subsys.c b/hw/nvme/subsys.c
index 192223d..dc7a968 100644
--- a/hw/nvme/subsys.c
+++ b/hw/nvme/subsys.c
@@ -61,6 +61,7 @@
 
     dc->realize = nvme_subsys_realize;
     dc->desc = "Virtual NVMe subsystem";
+    dc->hotpluggable = false;
 
     device_class_set_props(dc, nvme_subsystem_props);
 }