blkio_cgroup_conf->iops and ->bps are owned by blk-throttle and has no
reason to be defined in blkcg core.  Drop them and let conf setting
functions directly manipulate throtl_grp->bps[] and ->iops[].

This makes blkio_group_conf empty.  Drop it.
Signed-off-by: NTejun Heo <tj@kernel.org>