net: sched: update action implementations to support flags

Extend struct tc_action with new "tcfa_flags" field. Set the field in
tcf_idr_create() function and provide new helper
tcf_idr_create_from_flags() that derives 'cpustats' boolean from flags
value. Update individual hardware-offloaded actions init() to pass their
"flags" argument to new helper in order to skip percpu stats allocation
when user requested it through flags.

Signed-off-by: Vlad Buslov <vladbu@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/act_mpls.c

@@ -225,7 +225,7 @@ static int tcf_mpls_init(struct net *net, struct nlattr *nla,
 
 	if (!exists) {
 		ret = tcf_idr_create(tn, index, est, a,
-				     &act_mpls_ops, bind, true);
+				     &act_mpls_ops, bind, true, 0);
 		if (ret) {
 			tcf_idr_cleanup(tn, index);
 			return ret;