io_uring/rsrc: disassociate nodes and rsrc_data

Make rsrc nodes independent from rsrd_data, for that we keep ctx and
rsrc type in nodes.

Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/4f259abe9cd4eea6a3b4ed83508635218acd3c3f.1681822823.git.asml.silence@gmail.com


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