neighbour: fix nlmsg_pid in notifications

neigh notifications today carry pid 0 for nlmsg_pid
in all cases. This patch fixes it to carry calling process
pid when available. Applications (eg. quagga) rely on
nlmsg_pid to ignore notifications generated by their own
netlink operations. This patch follows the routing subsystem
which already sets this correctly.

Reported-by: Vivek Venkatraman <vivek@cumulusnetworks.com>
Signed-off-by: Roopa Prabhu <roopa@cumulusnetworks.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/atm/clip.c b/net/atm/clip.c
index 53b4ac0..ec527b6 100644
--- a/net/atm/clip.c
+++ b/net/atm/clip.c
@@ -106,7 +106,7 @@ static void unlink_clip_vcc(struct clip_vcc *clip_vcc)
 			entry->expires = jiffies - 1;
 			/* force resolution or expiration */
 			error = neigh_update(entry->neigh, NULL, NUD_NONE,
-					     NEIGH_UPDATE_F_ADMIN);
+					     NEIGH_UPDATE_F_ADMIN, 0);
 			if (error)
 				pr_crit("neigh_update failed with %d\n", error);
 			goto out;
@@ -481,7 +481,7 @@ static int clip_setentry(struct atm_vcc *vcc, __be32 ip)
 		link_vcc(clip_vcc, entry);
 	}
 	error = neigh_update(neigh, llc_oui, NUD_PERMANENT,
-			     NEIGH_UPDATE_F_OVERRIDE | NEIGH_UPDATE_F_ADMIN);
+			     NEIGH_UPDATE_F_OVERRIDE | NEIGH_UPDATE_F_ADMIN, 0);
 	neigh_release(neigh);
 	return error;
 }