net/ipv6/ndisc.c: make a function static

@@ -1594,10 +1594,11 @@
 	return ret;
 }
 
-int ndisc_ifinfo_sysctl_strategy(ctl_table *ctl, int __user *name, int nlen,
-				 void __user *oldval, size_t __user *oldlenp,
-				 void __user *newval, size_t newlen,
-				 void **context)
+static int ndisc_ifinfo_sysctl_strategy(ctl_table *ctl, int __user *name,
+					int nlen, void __user *oldval,
+					size_t __user *oldlenp,
+					void __user *newval, size_t newlen,
+					void **context)
 {
 	struct net_device *dev = ctl->extra1;
 	struct inet6_dev *idev;