virtio-md-pci: New parent type for virtio-mem-pci and virtio-pmem-pci

Let's add a new abstract "virtio memory device" type, and use it as
parent class of virtio-mem-pci and virtio-pmem-pci.

Message-ID: <20230711153445.514112-2-david@redhat.com>
Tested-by: Mario Casquero <mcasquer@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
diff --git a/hw/virtio/virtio-mem-pci.c b/hw/virtio/virtio-mem-pci.c
index b85c126..2ef0f07 100644
--- a/hw/virtio/virtio-mem-pci.c
+++ b/hw/virtio/virtio-mem-pci.c
@@ -142,14 +142,11 @@
 
 static const VirtioPCIDeviceTypeInfo virtio_mem_pci_info = {
     .base_name = TYPE_VIRTIO_MEM_PCI,
+    .parent = TYPE_VIRTIO_MD_PCI,
     .generic_name = "virtio-mem-pci",
     .instance_size = sizeof(VirtIOMEMPCI),
     .instance_init = virtio_mem_pci_instance_init,
     .class_init = virtio_mem_pci_class_init,
-    .interfaces = (InterfaceInfo[]) {
-        { TYPE_MEMORY_DEVICE },
-        { }
-    },
 };
 
 static void virtio_mem_pci_register_types(void)