net: sched: act: fix code style

This patch is used by subsequent patches. It fixes code style issues
caught by checkpatch.

Signed-off-by: Alexander Aring <aring@mojatatu.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c
index e6ff88f..abcd5f1 100644
--- a/net/sched/act_mirred.c
+++ b/net/sched/act_mirred.c
@@ -80,12 +80,12 @@ static int tcf_mirred_init(struct net *net, struct nlattr *nla,
 	bool exists = false;
 	int ret;
 
-	if (nla == NULL)
+	if (!nla)
 		return -EINVAL;
 	ret = nla_parse_nested(tb, TCA_MIRRED_MAX, nla, mirred_policy, NULL);
 	if (ret < 0)
 		return ret;
-	if (tb[TCA_MIRRED_PARMS] == NULL)
+	if (!tb[TCA_MIRRED_PARMS])
 		return -EINVAL;
 	parm = nla_data(tb[TCA_MIRRED_PARMS]);
 
@@ -117,7 +117,7 @@ static int tcf_mirred_init(struct net *net, struct nlattr *nla,
 	}
 
 	if (!exists) {
-		if (dev == NULL)
+		if (!dev)
 			return -EINVAL;
 		ret = tcf_idr_create(tn, parm->index, est, a,
 				     &act_mirred_ops, bind, true);