virtio_ring: make virtqueue_add_indirect_packed prettier

Align the arguments of virtqueue_add_indirect_packed() to the open ( to
make it look prettier.
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://lore.kernel.org/r/20211020112323.67466-2-xuanzhuo@linux.alibaba.comSigned-off-by: Michael S. Tsirkin <mst@redhat.com>