net: vrf: Fix setting NLM_F_EXCL flag when adding l3mdev rule

Only need 1 l3mdev FIB rule. Fix setting NLM_F_EXCL in the nlmsghdr.

Fixes: 1aa6c4f6b8cd8 ("net: vrf: Add l3mdev rules on first device create")
Signed-off-by: David Ahern <dsa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/vrf.c

@@ -1128,7 +1128,7 @@ static int vrf_fib_rule(const struct net_device *dev, __u8 family, bool add_it)
 		goto nla_put_failure;
 
 	/* rule only needs to appear once */
-	nlh->nlmsg_flags &= NLM_F_EXCL;
+	nlh->nlmsg_flags |= NLM_F_EXCL;
 
 	frh = nlmsg_data(nlh);
 	memset(frh, 0, sizeof(*frh));