io_uring: fix missed comment from *task_file rename

Fix comment referring to function "io_uring_del_task_file()", now called
"io_uring_del_tctx_node()".

Fixes: eef51daa

 ("io_uring: rename function *task_file")
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Link: https://lore.kernel.org/r/20211116175530.31608-1-kamal@canonical.com


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