netfilter: ipset: Removed invalid IPSET_ATTR_MARKMASK validation

Markmask is an u32, hence it can't be greater then 4294967295 ( i.e.
0xffffffff ). This was causing smatch warning:
 net/netfilter/ipset/ip_set_hash_gen.h:1084 hash_ipmark_create() warn:
 impossible condition '(markmask > 4294967295) => (0-u32max > u32max)'
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>

net/netfilter/ipset/ip_set_hash_gen.h

@@ -1093,7 +1093,7 @@ IPSET_TOKEN(HTYPE, _create)(struct net *net, struct ip_set *set,
 	if (tb[IPSET_ATTR_MARKMASK]) {
 		markmask = ntohl(nla_get_u32(tb[IPSET_ATTR_MARKMASK]));
 
-		if ((markmask > 4294967295u) || markmask == 0)
+		if (markmask == 0)
 			return -IPSET_ERR_INVALID_MARKMASK;
 	}
 #endif