ipv4: Namespecify tcp_keepalive_probes sysctl knob

This is required to have full tcp keepalive mechanism namespace
support.

Signed-off-by: Nikolay Borisov <kernel@kyup.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/net/netns/ipv4.h b/include/net/netns/ipv4.h
index 9e9bbeb..6e26ea2 100644
--- a/include/net/netns/ipv4.h
+++ b/include/net/netns/ipv4.h
@@ -95,6 +95,7 @@
 	u32 sysctl_tcp_probe_interval;
 
 	int sysctl_tcp_keepalive_time;
+	int sysctl_tcp_keepalive_probes;
 
 	struct ping_group_range ping_group_range;