Add bootindex parameter to net/block/fd device

If bootindex is specified on command line a string that describes device
in firmware readable way is added into sorted list. Later this list will
be passed into firmware to control boot order.

Signed-off-by: Gleb Natapov <gleb@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
diff --git a/hw/virtio-blk.c b/hw/virtio-blk.c
index e5f9b27..f62ccd1 100644
--- a/hw/virtio-blk.c
+++ b/hw/virtio-blk.c
@@ -548,6 +548,8 @@
     bdrv_set_removable(s->bs, 0);
     s->bs->buffer_alignment = conf->logical_block_size;
 
+    add_boot_device_path(conf->bootindex, dev, "/disk@0,0");
+
     return &s->vdev;
 }