io_uring/rsrc: remove unused io_rsrc_node::llist

->llist was needed for rsrc node destruction offload, which is removed
now. Get rid of the unused field.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/8e7d764c3f947489fde88d0927c3060d2e1bb599.1681822823.git.asml.silence@gmail.com


Signed-off-by: Jens Axboe <axboe@kernel.dk>