virtio: introduce virtio_queue_info struct and find_vqs_info() config op

virtio: introduce virtio_queue_info struct and find_vqs_info() config op

Introduce a structure virtio_queue_info to carry name, callback and ctx
together. In order to allow config implementations to accept config op
with array of virtio_queue_info structures, introduce a new
find_vqs_info() op. Do the needed conversion in virtio_find_vqs_ctx().
Note that whole virtio_find_vqs_ctx() is going to be eventually removed
at the and of this patchset.

Suggested-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Signed-off-by: Jiri Pirko <jiri@nvidia.com>
Message-Id: <20240708074814.1739223-5-jiri@resnulli.us>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>