netfilter: ipset: take into account cidr value for the from address when creating the set

When creating a set from a range expressed as a network like
10.1.1.172/29, the from address was taken as the IP address part and
not masked with the netmask from the cidr.
Signed-off-by: Jozsef Kadlecsik <kadlec@blackhole.kfki.hu>
Signed-off-by: Patrick McHardy <kaber@trash.net>

net/netfilter/ipset/ip_set_bitmap_ip.c

@@ -478,6 +478,7 @@ bitmap_ip_create(struct ip_set *set, struct nlattr *tb[], u32 flags)
 
 		if (cidr >= 32)
 			return -IPSET_ERR_INVALID_CIDR;
+		first_ip &= ip_set_hostmask(cidr);
 		last_ip = first_ip | ~ip_set_hostmask(cidr);
 	} else
 		return -IPSET_ERR_PROTOCOL;