IPv6: only update the lifetime of the relevant temporary address

When receiving a prefix information from a routeur, only update the
lifetimes of the temporary address associated with that prefix.

Otherwise if one deprecated prefix is advertized, all your temporary
addresses will become deprecated.
Signed-off-by: Benoit Boissinot <benoit.boissinot@ens-lyon.org>
Acked-by: YOSHIFUJI Hideaki <yoshfuji@linux-ipv6.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv6/addrconf.c

@@ -1831,6 +1831,9 @@ ok:
 				 * lifetimes of an existing temporary address
 				 * when processing a Prefix Information Option.
 				 */
+				if (ifp != ift->ifpub)
+					continue;
+
 				spin_lock(&ift->lock);
 				flags = ift->flags;
 				if (ift->valid_lft > valid_lft &&