block: fix kerneldoc for disk_register_independent_access__ranges()

The naming got changed as part of a revision of the patchset, but the
kerneldoc apparently never got updated. Fix it.

Reported-by: kernel test robot <lkp@intel.com>
Fixes: a2247f19 ("block: Add independent access ranges support")
Signed-off-by: Jens Axboe <axboe@kernel.dk>