[PKT_SCHED]: Fix datalen check in tcf_simp_init().

datalen is unsigned so it can never be less than zero,
but that's ok because the attribute passed to nla_len()
has been validated and therefore a negative return
value is impossible.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/sched/act_simple.c

@@ -115,7 +115,7 @@ static int tcf_simp_init(struct nlattr *nla, struct nlattr *est,
 		return -EINVAL;
 
 	datalen = nla_len(tb[TCA_DEF_DATA]);
-	if (datalen <= 0)
+	if (datalen == 0)
 		return -EINVAL;
 
 	pc = tcf_hash_check(parm->index, a, bind, &simp_hash_info);