Revert "virtio: don't call device on !vm_running"

This reverts commit a1bc7b827e422e1ff065640d8ec5347c4aadfcd8.
    virtio: don't call device on !vm_running
It turns out that virtio net assumes that vm_running
is updated before device status callback in many places,
so this change leads to asserts.
Previous commit fixes the root issue that motivated
a1bc7b827e422e1ff065640d8ec5347c4aadfcd8 differently,
so there's no longer a need for this change.

In the future, we might be able to drop checking vm_running
completely, and check vm state directly.
Reported-by: NDietmar Maurer <dietmar@proxmox.com>
Cc: qemu-stable@nongnu.org
Acked-by: NJason Wang <jasowang@redhat.com>
Signed-off-by: NMichael S. Tsirkin <mst@redhat.com>

hw/virtio/virtio.c

@@ -1108,10 +1108,7 @@ static void virtio_vmstate_change(void *opaque, int running, RunState state)
     BusState *qbus = qdev_get_parent_bus(DEVICE(vdev));
     VirtioBusClass *k = VIRTIO_BUS_GET_CLASS(qbus);
     bool backend_run = running && (vdev->status & VIRTIO_CONFIG_S_DRIVER_OK);
-
-    if (running) {
-        vdev->vm_running = running;
-    }
+    vdev->vm_running = running;
 
     if (backend_run) {
         virtio_set_status(vdev, vdev->status);
@@ -1124,10 +1121,6 @@ static void virtio_vmstate_change(void *opaque, int running, RunState state)
     if (!backend_run) {
         virtio_set_status(vdev, vdev->status);
     }
-
-    if (!running) {
-        vdev->vm_running = running;
-    }
 }
 
 void virtio_init(VirtIODevice *vdev, const char *name,