[NET]: Fix sparse warnings

Of this type, mostly:

CHECK   net/ipv6/netfilter.c
net/ipv6/netfilter.c:96:12: warning: symbol 'ipv6_netfilter_init' was not declared. Should it be static?
net/ipv6/netfilter.c:101:6: warning: symbol 'ipv6_netfilter_fini' was not declared. Should it be static?

Signed-off-by: Arnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

include/linux/if_frad.h

@@ -191,10 +191,12 @@ struct frad_local
    int               buffer;		/* current buffer for S508 firmware */
 };
 
-extern void dlci_ioctl_set(int (*hook)(unsigned int, void __user *));
-
 #endif /* __KERNEL__ */
 
 #endif /* CONFIG_DLCI || CONFIG_DLCI_MODULE */
 
+#ifdef __KERNEL__
+extern void dlci_ioctl_set(int (*hook)(unsigned int, void __user *));
+#endif
+
 #endif