block: Remove bdrv_query_block_node_info

The last call site of this function has been removed by commit
c04d0ab0 ("qemu-img: Let info print block graph").

Reviewed-by: Claudio Fontana <cfontana@suse.de>
Signed-off-by: Fabiano Rosas <farosas@suse.de>
Message-ID: <20230901184605.32260-2-farosas@suse.de>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>