ublk: remove misleading "ubq" in "ubq_complete_io_cmd()"

ubq_complete_io_cmd() doesn't interact with a ublk queue, so "ubq" in
the name is confusing. Most likely "ubq" was meant to be "ublk".

Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20250430225234.2676781-4-csander@purestorage.com


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