net: sched: don't set tunnel for decap action

Action tunnel_key doesn't have a metadata/tunnel for release(decap) action.
Drivers do not dereference entry->tunnel pointer for that action type, so
this behavior doesn't result in a crash at the moment. However, this needs
to be corrected as a preparation for updating hardware offloads API to not
rely on rtnl lock, for which flow_action code will copy the tunnel data to
temporary buffer to prevent concurrent action overwrite from
invalidating/freeing it.

Fixes: 3a7b68617de7 ("cls_api: add translator to flow_action representation")
Signed-off-by: Vlad Buslov <[e-mail]>
Signed-off-by: David S. Miller <[e-mail]>

net/sched/cls_api.c

···
 			entry->tunnel = tcf_tunnel_info(act);
 		} else if (is_tcf_tunnel_release(act)) {
 			entry->id = FLOW_ACTION_TUNNEL_DECAP;
-			entry->tunnel = tcf_tunnel_info(act);
 		} else if (is_tcf_pedit(act)) {
 			for (k = 0; k < tcf_pedit_nkeys(act); k++) {
 				switch (tcf_pedit_cmd(act, k)) {