IPv6: Extend 'fib_notify_on_flag_change' sysctl

Add the value '2' to 'fib_notify_on_flag_change' to allow sending
notifications only for failed route installation.

Separate value is added for such notifications because there are less of
them, so they do not impact performance and some users will find them more
important.

Signed-off-by: Amit Cohen <amcohen@nvidia.com>
Signed-off-by: Ido Schimmel <idosch@nvidia.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/ipv6/sysctl_net_ipv6.c b/net/ipv6/sysctl_net_ipv6.c
index 392ef01..263ab43 100644
--- a/net/ipv6/sysctl_net_ipv6.c
+++ b/net/ipv6/sysctl_net_ipv6.c
@@ -167,7 +167,7 @@ static struct ctl_table ipv6_table_template[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_dointvec_minmax,
 		.extra1         = SYSCTL_ZERO,
-		.extra2         = SYSCTL_ONE,
+		.extra2         = &two,
 	},
 	{ }
 };