[NETFILTER]: ipt_DNAT: accept port randomization option

Also accept the --random option for DNAT to allow randomly selecting a
destination port from the given range.
Signed-off-by: NPatrick McHardy <kaber@trash.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/ipv4/netfilter/nf_nat_rule.c

@@ -226,10 +226,6 @@ static int ipt_dnat_checkentry(const char *tablename,
 		printk("DNAT: multiple ranges no longer supported\n");
 		return 0;
 	}
-	if (mr->range[0].flags & IP_NAT_RANGE_PROTO_RANDOM) {
-		printk("DNAT: port randomization not supported\n");
-		return 0;
-	}
 	return 1;
 }