net/sched: avoid double free on matchall reoffload

Avoid freeing cls_mall.rule twice when failing to setup flow_action
offload used in the hardware intermediate representation. This is
achieved by returning 0 when the setup fails but the skip software
flag has not been set.

Fixes: f00cbf19 ("net/sched: use the hardware intermediate representation for matchall")
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Pieter Jansen van Vuuren <pieter.jansenvanvuuren@netronome.com>
Reviewed-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sched/cls_matchall.c

@@ -308,6 +308,7 @@ static int mall_reoffload(struct tcf_proto *tp, bool add, tc_setup_cb_t *cb,
 			NL_SET_ERR_MSG_MOD(extack, "Failed to setup flow action");
 			return err;
 		}
+		return 0;
 	}
 
 	err = cb(TC_SETUP_CLSMATCHALL, &cls_mall, cb_priv);