task_work: add kerneldoc annotation for 'data' argument

A previous commit changed the arguments to task_work_cancel_match(), but
didn't document all of them.

Link: https://lkml.kernel.org/r/93938bff-baa3-4091-85f5-784aae297a07@kernel.dk


Fixes: c7aab1a7 ("task_work: add helper for more targeted task_work canceling")
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202309120307.zis3yQGe-lkp@intel.com/


Acked-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>