io_uring: use IO_REQ_LINK_FLAGS more

Replace the 2 instances of REQ_F_LINK | REQ_F_HARDLINK with
the more commonly used IO_REQ_LINK_FLAGS.

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Link: https://lore.kernel.org/r/20250211202002.3316324-1-csander@purestorage.com


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