net: Convert all sysctl registrations to register_net_sysctl

This results in code with less boiler plate that is a bit easier
to read.

Additionally stops us from using compatibility code in the sysctl
core, hastening the day when the compatibility code can be removed.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Acked-by: Pavel Emelyanov <xemul@parallels.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/ipv4/xfrm4_policy.c

@@ -298,8 +298,8 @@ void __init xfrm4_init(int rt_max_size)
 	xfrm4_state_init();
 	xfrm4_policy_init();
 #ifdef CONFIG_SYSCTL
-	sysctl_hdr = register_net_sysctl_table(&init_net, net_ipv4_ctl_path,
-						xfrm4_policy_table);
+	sysctl_hdr = register_net_sysctl(&init_net, "net/ipv4",
+					 xfrm4_policy_table);
 #endif
 }