net: rcu-ify tcf_proto

rcu'ify tcf_proto this allows calling tc_classify() without holding
any locks. Updaters are protected by RTNL.

This patch prepares the core net_sched infrastracture for running
the classifier/action chains without holding the qdisc lock however
it does nothing to ensure cls_xxx and act_xxx types also work without
locking. Additional patches are required to address the fall out.

Signed-off-by: John Fastabend <john.r.fastabend@intel.com>
Acked-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --cc include/net/sch_generic.h
Simple merge

diff --cc net/sched/cls_api.c
Simple merge

diff --cc net/sched/sch_api.c
Simple merge

diff --cc net/sched/sch_atm.c
Simple merge

diff --cc net/sched/sch_cbq.c
Simple merge

diff --cc net/sched/sch_choke.c
Simple merge

diff --cc net/sched/sch_drr.c
Simple merge

diff --cc net/sched/sch_dsmark.c
Simple merge

diff --cc net/sched/sch_fq_codel.c
Simple merge

diff --cc net/sched/sch_hfsc.c
Simple merge

diff --cc net/sched/sch_htb.c
Simple merge

diff --cc net/sched/sch_ingress.c
Simple merge

diff --cc net/sched/sch_multiq.c
Simple merge

diff --cc net/sched/sch_prio.c
Simple merge

diff --cc net/sched/sch_qfq.c
Simple merge

diff --cc net/sched/sch_sfb.c
Simple merge

diff --cc net/sched/sch_sfq.c
Simple merge