netprio_cgroup: pass around @css instead of @cgroup and kill struct cgroup_netprio_state
cgroup controller API will be converted to primarily use struct
cgroup_subsys_state instead of struct cgroup. In preparation, make
the internal functions of netprio_cgroup pass around @css instead of
@cgrp.
While at it, kill struct cgroup_netprio_state which only contained
struct cgroup_subsys_state without serving any purpose. All functions
are converted to deal with @css directly.
This patch shouldn't cause any behavior differences.
Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Li Zefan <lizefan@huawei.com> Acked-by: Neil Horman <nhorman@tuxdriver.com> Acked-by: David S. Miller <davem@davemloft.net>