vDPA: report virtio-block read-only info to user space

This commit report read-only information of
virtio-blk devices to user space.

Signed-off-by: Zhu Lingshan <lingshan.zhu@intel.com>
Message-Id: <20240218185606.13509-10-lingshan.zhu@intel.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>