net_sched: act: hide struct tcf_common from API

Now we can totally hide it from modules. tcf_hash_*() API's
will operate on struct tc_action, modules don't need to care about
the details.

Cc: Jamal Hadi Salim <jhs@mojatatu.com>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Cong Wang <xiyou.wangcong@gmail.com>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/tc_act/tc_csum.h

@@ -9,7 +9,7 @@ struct tcf_csum {
 
 	u32 update_flags;
 };
-#define to_tcf_csum(pc) \
-	container_of(pc,struct tcf_csum,common)
+#define to_tcf_csum(a) \
+	container_of(a->priv,struct tcf_csum,common)
 
 #endif /* __NET_TC_CSUM_H */