net: CONFIG_NET_SYSCTL_DEV: make per interface dev_snmp6 proc entries optional
        
Use same CONFIG_NET_SYSCTL_DEV config option (we should probably
rename it to a better name) to enable/disable per interface dev_snmp6
proc entries.

--- //packages/linux_2.6.31/rc7/src/include/net/ipv6.h
+++ //packages/linux_2.6.31/rc7/src/include/net/ipv6.h
@@ -604,8 +604,14 @@
 extern void udplite6_proc_exit(void);
 extern int  ipv6_misc_proc_init(void);
 extern void ipv6_misc_proc_exit(void);
+
+#ifdef CONFIG_NET_SYSCTL_DEV
 extern int snmp6_register_dev(struct inet6_dev *idev);
 extern int snmp6_unregister_dev(struct inet6_dev *idev);
+#else
+static inline int snmp6_register_dev(struct inet6_dev *idev) { return 0; }
+static inline int snmp6_unregister_dev(struct inet6_dev *idev) { return 0; }
+#endif
 
 #else
 static inline int ac6_proc_init(struct net *net) { return 0; }
--- //packages/linux_2.6.31/rc7/src/net/ipv6/proc.c
+++ //packages/linux_2.6.31/rc7/src/net/ipv6/proc.c
@@ -232,6 +232,7 @@
 	.release = single_release,
 };
 
+#ifdef CONFIG_NET_SYSCTL_DEV
 int snmp6_register_dev(struct inet6_dev *idev)
 {
 	struct proc_dir_entry *p;
@@ -266,6 +267,7 @@
 	idev->stats.proc_dir_entry = NULL;
 	return 0;
 }
+#endif
 
 static int ipv6_proc_init_net(struct net *net)
 {