virtio-net: introduce flush_or_purge_queued_packets()

virtio-net: introduce flush_or_purge_queued_packets()

Introduce the fucntion flush_or_purge_queued_packets(), it will be
used in device reset and virtqueue reset. Therefore, we extract the
common logic as a new function.

Signed-off-by: Kangjie Xu <kangjie.xu@linux.alibaba.com>
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20221017092558.111082-12-xuanzhuo@linux.alibaba.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>